Remove the old task model

pkg/analyzer/lib/src/generated/engine.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library engine;
 
 import 'dart:async';
 import 'dart:collection';
-import 'dart:math' as math;
 
 import 'package:analyzer/source/embedder.dart';
 import 'package:analyzer/src/cancelable_future.dart';
-import 'package:analyzer/src/context/cache.dart' as cache;
-import 'package:analyzer/src/context/context.dart' as newContext;
-import 'package:analyzer/src/generated/incremental_resolution_validator.dart';
+import 'package:analyzer/src/context/cache.dart';
+import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/plugin/command_line_plugin.dart';
 import 'package:analyzer/src/plugin/engine_plugin.dart';
 import 'package:analyzer/src/plugin/options_plugin.dart';
-import 'package:analyzer/src/services/lint.dart';
 import 'package:analyzer/src/task/manager.dart';
 import 'package:analyzer/task/dart.dart';
-import 'package:analyzer/task/model.dart' as newContext;
 import 'package:analyzer/task/model.dart';
 import 'package:html/dom.dart' show Document;
 import 'package:path/path.dart' as pathos;
 import 'package:plugin/manager.dart';
 import 'package:plugin/plugin.dart';
 
 import '../../instrumentation/instrumentation.dart';
 import 'ast.dart';
 import 'constant.dart';
 import 'element.dart';
 import 'error.dart';
-import 'error_verifier.dart';
 import 'html.dart' as ht;
-import 'incremental_resolver.dart'
-    show IncrementalResolver, PoorMansIncrementalResolver;
-import 'incremental_scanner.dart';
 import 'java_core.dart';
 import 'java_engine.dart';
-import 'parser.dart' show Parser, IncrementalParser;
 import 'resolver.dart';
-import 'scanner.dart';
-import 'sdk.dart' show DartSdk;
 import 'source.dart';
-import 'utilities_collection.dart';
 import 'utilities_general.dart';
 
 /**
  * Used by [AnalysisOptions] to allow function bodies to be analyzed in some
  * sources but not others.
  */
 typedef bool AnalyzeFunctionBodiesPredicate(Source source);
 
 /**
- * Type of callback functions used by PendingFuture.  Functions of this type
- * should perform a computation based on the data in [sourceEntry] and return
- * it.  If the computation can't be performed yet because more analysis is
- * needed, null should be returned.
- *
- * The function may also throw an exception, in which case the corresponding
- * future will be completed with failure.
- *
- * Since this function is called while the state of analysis is being updated,
- * it should be free of side effects so that it doesn't cause reentrant
- * changes to the analysis state.
- */
-typedef T PendingFutureComputer<T>(SourceEntry sourceEntry);
-
-/**
- * An LRU cache of information related to analysis.
- */
-class AnalysisCache {
-  /**
-   * A flag used to control whether trace information should be produced when
-   * the content of the cache is modified.
-   */
-  static bool _TRACE_CHANGES = false;
-
-  /**
-   * A list containing the partitions of which this cache is comprised.
-   */
-  final List<CachePartition> _partitions;
-
-  /**
-   * Initialize a newly created cache to have the given [_partitions]. The
-   * partitions will be searched in the order in which they appear in the list,
-   * so the most specific partition (usually an [SdkCachePartition]) should be
-   * first and the most general (usually a [UniversalCachePartition]) last.
-   */
-  AnalysisCache(this._partitions);
-
-  /**
-   * Return the number of entries in this cache that have an AST associated with
-   * them.
-   */
-  int get astSize => _partitions[_partitions.length - 1].astSize;
-
-  /**
-   * Return information about each of the partitions in this cache.
-   */
-  List<AnalysisContextStatistics_PartitionData> get partitionData {
-    int count = _partitions.length;
-    List<AnalysisContextStatistics_PartitionData> data =
-        new List<AnalysisContextStatistics_PartitionData>(count);
-    for (int i = 0; i < count; i++) {
-      CachePartition partition = _partitions[i];
-      data[i] = new AnalysisContextStatisticsImpl_PartitionDataImpl(
-          partition.astSize, partition.map.length);
-    }
-    return data;
-  }
-
-  /**
-   * Record that the AST associated with the given [source] was just read from
-   * the cache.
-   */
-  void accessedAst(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        _partitions[i].accessedAst(source);
-        return;
-      }
-    }
-  }
-
-  /**
-   * Return the entry associated with the given [source].
-   */
-  SourceEntry get(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        return _partitions[i].get(source);
-      }
-    }
-    //
-    // We should never get to this point because the last partition should
-    // always be a universal partition, except in the case of the SDK context,
-    // in which case the source should always be part of the SDK.
-    //
-    return null;
-  }
-
-  /**
-   * Return context that owns the given [source].
-   */
-  InternalAnalysisContext getContextFor(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        return _partitions[i].context;
-      }
-    }
-    //
-    // We should never get to this point because the last partition should
-    // always be a universal partition, except in the case of the SDK context,
-    // in which case the source should always be part of the SDK.
-    //
-    AnalysisEngine.instance.logger.logInformation(
-        "Could not find context for ${source.fullName}",
-        new CaughtException(new AnalysisException(), null));
-    return null;
-  }
-
-  /**
-   * Return an iterator returning all of the map entries mapping sources to
-   * cache entries.
-   */
-  MapIterator<Source, SourceEntry> iterator() {
-    int count = _partitions.length;
-    List<Map<Source, SourceEntry>> maps =
-        new List<Map<Source, SourceEntry>>(count);
-    for (int i = 0; i < count; i++) {
-      maps[i] = _partitions[i].map;
-    }
-    return new MultipleMapIterator<Source, SourceEntry>(maps);
-  }
-
-  /**
-   * Associate the given [entry] with the given [source].
-   */
-  void put(Source source, SourceEntry entry) {
-    entry.fixExceptionState();
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        if (_TRACE_CHANGES) {
-          try {
-            SourceEntry oldEntry = _partitions[i].get(source);
-            if (oldEntry == null) {
-              AnalysisEngine.instance.logger.logInformation(
-                  "Added a cache entry for '${source.fullName}'.");
-            } else {
-              AnalysisEngine.instance.logger.logInformation(
-                  "Modified the cache entry for ${source.fullName}'. Diff = ${entry.getDiff(oldEntry)}");
-            }
-          } catch (exception) {
-            // Ignored
-            JavaSystem.currentTimeMillis();
-          }
-        }
-        _partitions[i].put(source, entry);
-        return;
-      }
-    }
-  }
-
-  /**
-   * Remove all information related to the given [source] from this cache.
-   * Return the entry associated with the source, or `null` if there was cache
-   * entry for the source.
-   */
-  SourceEntry remove(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        if (_TRACE_CHANGES) {
-          try {
-            AnalysisEngine.instance.logger.logInformation(
-                "Removed the cache entry for ${source.fullName}'.");
-          } catch (exception) {
-            // Ignored
-            JavaSystem.currentTimeMillis();
-          }
-        }
-        return _partitions[i].remove(source);
-      }
-    }
-    return null;
-  }
-
-  /**
-   * Record that the AST associated with the given [source] was just removed
-   * from the cache.
-   */
-  void removedAst(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        _partitions[i].removedAst(source);
-        return;
-      }
-    }
-  }
-
-  /**
-   * Return the number of sources that are mapped to cache entries.
-   */
-  int size() {
-    int size = 0;
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      size += _partitions[i].size();
-    }
-    return size;
-  }
-
-  /**
-   * Record that the AST associated with the given [source] was just stored to
-   * the cache.
-   */
-  void storedAst(Source source) {
-    int count = _partitions.length;
-    for (int i = 0; i < count; i++) {
-      if (_partitions[i].contains(source)) {
-        _partitions[i].storedAst(source);
-        return;
-      }
-    }
-  }
-}
-
-/**
  * A context in which a single analysis can be performed and incrementally
  * maintained. The context includes such information as the version of the SDK
  * being analyzed against as well as the package-root used to resolve 'package:'
  * URI's. (Both of which are known indirectly through the [SourceFactory].)
  *
  * An analysis context also represents the state of the analysis, which includes
  * knowing which sources have been included in the analysis (either directly or
  * indirectly) and the results of the analysis. Sources must be added and
  * removed from the context using the method [applyChanges], which is also used
  * to notify the context when sources have been modified and, consequently,
@@ skipping 627 matching lines @@
   /**
    * Check the cache for any invalid entries (entries whose modification time
    * does not match the modification time of the source associated with the
    * entry). Invalid entries will be marked as invalid so that the source will
    * be re-analyzed. Return `true` if at least one entry was invalid.
    */
   bool validateCacheConsistency();
 }
 
 /**
- * An [AnalysisContext].
- */
-class AnalysisContextImpl implements InternalAnalysisContext {
-  /**
-   * The difference between the maximum cache size and the maximum priority
-   * order size. The priority list must be capped so that it is less than the
-   * cache size. Failure to do so can result in an infinite loop in
-   * performAnalysisTask() because re-caching one AST structure can cause
-   * another priority source's AST structure to be flushed.
-   */
-  static int _PRIORITY_ORDER_SIZE_DELTA = 4;
-
-  /**
-   * A flag indicating whether trace output should be produced as analysis tasks
-   * are performed. Used for debugging.
-   */
-  static bool _TRACE_PERFORM_TASK = false;
-
-  /**
-   * The next context identifier.
-   */
-  static int _NEXT_ID = 0;
-
-  /**
-   * The unique identifier of this context.
-   */
-  final int _id = _NEXT_ID++;
-
-  /**
-   * A client-provided name used to identify this context, or `null` if the
-   * client has not provided a name.
-   */
-  String name;
-
-  /**
-   * Configuration data associated with this context.
-   */
-  final HashMap<ResultDescriptor, Object> _configurationData =
-      new HashMap<ResultDescriptor, Object>();
-
-  /**
-   * The set of analysis options controlling the behavior of this context.
-   */
-  AnalysisOptionsImpl _options = new AnalysisOptionsImpl();
-
-  /// The embedder yaml locator for this context.
-  EmbedderYamlLocator _embedderYamlLocator = new EmbedderYamlLocator(null);
-
-  /**
-   * A flag indicating whether errors related to implicitly analyzed sources
-   * should be generated and reported.
-   */
-  bool _generateImplicitErrors = true;
-
-  /**
-   * A flag indicating whether errors related to sources in the SDK should be
-   * generated and reported.
-   */
-  bool _generateSdkErrors = true;
-
-  /**
-   * A flag indicating whether this context is disposed.
-   */
-  bool _disposed = false;
-
-  /**
-   * A cache of content used to override the default content of a source.
-   */
-  ContentCache _contentCache = new ContentCache();
-
-  /**
-   * The source factory used to create the sources that can be analyzed in this
-   * context.
-   */
-  SourceFactory _sourceFactory;
-
-  /**
-   * The set of declared variables used when computing constant values.
-   */
-  DeclaredVariables _declaredVariables = new DeclaredVariables();
-
-  /**
-   * A source representing the core library.
-   */
-  Source _coreLibrarySource;
-
-  /**
-   * A source representing the async library.
-   */
-  Source _asyncLibrarySource;
-
-  /**
-   * The partition that contains analysis results that are not shared with other
-   * contexts.
-   */
-  CachePartition _privatePartition;
-
-  /**
-   * A table mapping the sources known to the context to the information known
-   * about the source.
-   */
-  AnalysisCache _cache;
-
-  /**
-   * A list containing sources for which data should not be flushed.
-   */
-  List<Source> _priorityOrder = Source.EMPTY_LIST;
-
-  /**
-   * A map from all sources for which there are futures pending to a list of
-   * the corresponding PendingFuture objects.  These sources will be analyzed
-   * in the same way as priority sources, except with higher priority.
-   *
-   * TODO(paulberry): since the size of this map is not constrained (as it is
-   * for _priorityOrder), we run the risk of creating an analysis loop if
-   * re-caching one AST structure causes the AST structure for another source
-   * with pending futures to be flushed.  However, this is unlikely to happen
-   * in practice since sources are removed from this hash set as soon as their
-   * futures have completed.
-   */
-  HashMap<Source, List<PendingFuture>> _pendingFutureSources =
-      new HashMap<Source, List<PendingFuture>>();
-
-  /**
-   * A list containing sources whose AST structure is needed in order to resolve
-   * the next library to be resolved.
-   */
-  HashSet<Source> _neededForResolution = null;
-
-  /**
-   * A table mapping sources to the change notices that are waiting to be
-   * returned related to that source.
-   */
-  HashMap<Source, ChangeNoticeImpl> _pendingNotices =
-      new HashMap<Source, ChangeNoticeImpl>();
-
-  /**
-   * The object used to record the results of performing an analysis task.
-   */
-  AnalysisContextImpl_AnalysisTaskResultRecorder _resultRecorder;
-
-  /**
-   * Cached information used in incremental analysis or `null` if none.
-   */
-  IncrementalAnalysisCache _incrementalAnalysisCache;
-
-  /**
-   * The [TypeProvider] for this context, `null` if not yet created.
-   */
-  TypeProvider _typeProvider;
-
-  /**
-   * The [TypeSystem] for this context, `null` if not yet created.
-   */
-  TypeSystem _typeSystem;
-
-  /**
-   * The object used to manage the list of sources that need to be analyzed.
-   */
-  WorkManager _workManager = new WorkManager();
-
-  /**
-   * The [Stopwatch] of the current "perform tasks cycle".
-   */
-  Stopwatch _performAnalysisTaskStopwatch;
-
-  /**
-   * The controller for sending [SourcesChangedEvent]s.
-   */
-  StreamController<SourcesChangedEvent> _onSourcesChangedController;
-
-  /**
-   * A subscription for a stream of events indicating when files are (and are
-   * not) being implicitly analyzed.
-   */
-  StreamController<ImplicitAnalysisEvent> _implicitAnalysisEventsController;
-
-  /**
-   * The listeners that are to be notified when various analysis results are
-   * produced in this context.
-   */
-  List<AnalysisListener> _listeners = new List<AnalysisListener>();
-
-  /**
-   * The most recently incrementally resolved source, or `null` when it was
-   * already validated, or the most recent change was not incrementally resolved.
-   */
-  Source incrementalResolutionValidation_lastUnitSource;
-
-  /**
-   * The most recently incrementally resolved library source, or `null` when it
-   * was already validated, or the most recent change was not incrementally
-   * resolved.
-   */
-  Source incrementalResolutionValidation_lastLibrarySource;
-
-  /**
-   * The result of incremental resolution result of
-   * [incrementalResolutionValidation_lastSource].
-   */
-  CompilationUnit incrementalResolutionValidation_lastUnit;
-
-  /**
-   * A factory to override how the [ResolverVisitor] is created.
-   */
-  ResolverVisitorFactory resolverVisitorFactory;
-
-  /**
-   * A factory to override how the [TypeResolverVisitor] is created.
-   */
-  TypeResolverVisitorFactory typeResolverVisitorFactory;
-
-  /**
-   * A factory to override how [LibraryResolver] is created.
-   */
-  LibraryResolverFactory libraryResolverFactory;
-
-  /**
-   * Initialize a newly created analysis context.
-   */
-  AnalysisContextImpl() {
-    _resultRecorder = new AnalysisContextImpl_AnalysisTaskResultRecorder(this);
-    _privatePartition = new UniversalCachePartition(
-        this,
-        AnalysisOptionsImpl.DEFAULT_CACHE_SIZE,
-        new AnalysisContextImpl_ContextRetentionPolicy(this));
-    _cache = createCacheFromSourceFactory(null);
-    _onSourcesChangedController =
-        new StreamController<SourcesChangedEvent>.broadcast();
-    _implicitAnalysisEventsController =
-        new StreamController<ImplicitAnalysisEvent>.broadcast();
-  }
-
-  @override
-  AnalysisCache get analysisCache => _cache;
-
-  @override
-  AnalysisOptions get analysisOptions => _options;
-
-  @override
-  void set analysisOptions(AnalysisOptions options) {
-    bool needsRecompute = this._options.analyzeFunctionBodiesPredicate !=
-            options.analyzeFunctionBodiesPredicate ||
-        this._options.generateImplicitErrors !=
-            options.generateImplicitErrors ||
-        this._options.generateSdkErrors != options.generateSdkErrors ||
-        this._options.dart2jsHint != options.dart2jsHint ||
-        (this._options.hint && !options.hint) ||
-        this._options.preserveComments != options.preserveComments ||
-        this._options.strongMode != options.strongMode ||
-        this._options.enableAssertMessage != options.enableAssertMessage ||
-        this._options.enableStrictCallChecks !=
-            options.enableStrictCallChecks ||
-        this._options.enableSuperMixins != options.enableSuperMixins;
-    int cacheSize = options.cacheSize;
-    if (this._options.cacheSize != cacheSize) {
-      this._options.cacheSize = cacheSize;
-      //cache.setMaxCacheSize(cacheSize);
-      _privatePartition.maxCacheSize = cacheSize;
-      //
-      // Cap the size of the priority list to being less than the cache size.
-      // Failure to do so can result in an infinite loop in
-      // performAnalysisTask() because re-caching one AST structure
-      // can cause another priority source's AST structure to be flushed.
-      //
-      // TODO(brianwilkerson) Remove this constraint when the new task model is
-      // implemented.
-      //
-      int maxPriorityOrderSize = cacheSize - _PRIORITY_ORDER_SIZE_DELTA;
-      if (_priorityOrder.length > maxPriorityOrderSize) {
-        _priorityOrder = _priorityOrder.sublist(0, maxPriorityOrderSize);
-      }
-    }
-    this._options.analyzeFunctionBodiesPredicate =
-        options.analyzeFunctionBodiesPredicate;
-    this._options.generateImplicitErrors = options.generateImplicitErrors;
-    this._options.generateSdkErrors = options.generateSdkErrors;
-    this._options.dart2jsHint = options.dart2jsHint;
-    this._options.enableAssertMessage = options.enableAssertMessage;
-    this._options.enableStrictCallChecks = options.enableStrictCallChecks;
-    this._options.enableSuperMixins = options.enableSuperMixins;
-    this._options.hint = options.hint;
-    this._options.incremental = options.incremental;
-    this._options.incrementalApi = options.incrementalApi;
-    this._options.incrementalValidation = options.incrementalValidation;
-    this._options.lint = options.lint;
-    this._options.preserveComments = options.preserveComments;
-    this._options.strongMode = options.strongMode;
-    _generateImplicitErrors = options.generateImplicitErrors;
-    _generateSdkErrors = options.generateSdkErrors;
-    if (needsRecompute) {
-      _invalidateAllLocalResolutionInformation(false);
-    }
-  }
-
-  @override
-  void set analysisPriorityOrder(List<Source> sources) {
-    if (sources == null || sources.isEmpty) {
-      _priorityOrder = Source.EMPTY_LIST;
-    } else {
-      while (sources.remove(null)) {
-        // Nothing else to do.
-      }
-      if (sources.isEmpty) {
-        _priorityOrder = Source.EMPTY_LIST;
-      }
-      //
-      // Cap the size of the priority list to being less than the cache size.
-      // Failure to do so can result in an infinite loop in
-      // performAnalysisTask() because re-caching one AST structure
-      // can cause another priority source's AST structure to be flushed.
-      //
-      int count = math.min(
-          sources.length, _options.cacheSize - _PRIORITY_ORDER_SIZE_DELTA);
-      _priorityOrder = new List<Source>(count);
-      for (int i = 0; i < count; i++) {
-        _priorityOrder[i] = sources[i];
-      }
-      // Ensure entries for every priority source.
-      for (var source in _priorityOrder) {
-        SourceEntry entry = _getReadableSourceEntry(source);
-        if (entry == null) {
-          _createSourceEntry(source, false);
-        }
-      }
-    }
-  }
-
-  @override
-  set contentCache(ContentCache value) {
-    _contentCache = value;
-  }
-
-  @override
-  DeclaredVariables get declaredVariables => _declaredVariables;
-
-  @override
-  EmbedderYamlLocator get embedderYamlLocator => _embedderYamlLocator;
-
-  @override
-  List<AnalysisTarget> get explicitTargets {
-    List<AnalysisTarget> targets = <AnalysisTarget>[];
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      if (iterator.value.explicitlyAdded) {
-        targets.add(iterator.key);
-      }
-    }
-    return targets;
-  }
-
-  @override
-  List<Source> get htmlSources => _getSources(SourceKind.HTML);
-
-  @override
-  Stream<ImplicitAnalysisEvent> get implicitAnalysisEvents =>
-      _implicitAnalysisEventsController.stream;
-
-  @override
-  bool get isDisposed => _disposed;
-
-  @override
-  List<Source> get launchableClientLibrarySources {
-    // TODO(brianwilkerson) This needs to filter out libraries that do not
-    // reference dart:html, either directly or indirectly.
-    List<Source> sources = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      SourceEntry sourceEntry = iterator.value;
-      if (sourceEntry.kind == SourceKind.LIBRARY && !source.isInSystemLibrary) {
-//          DartEntry dartEntry = (DartEntry) sourceEntry;
-//          if (dartEntry.getValue(DartEntry.IS_LAUNCHABLE) && dartEntry.getValue(DartEntry.IS_CLIENT)) {
-        sources.add(source);
-//          }
-      }
-    }
-    return sources;
-  }
-
-  @override
-  List<Source> get launchableServerLibrarySources {
-    // TODO(brianwilkerson) This needs to filter out libraries that reference
-    // dart:html, either directly or indirectly.
-    List<Source> sources = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      SourceEntry sourceEntry = iterator.value;
-      if (sourceEntry.kind == SourceKind.LIBRARY && !source.isInSystemLibrary) {
-//          DartEntry dartEntry = (DartEntry) sourceEntry;
-//          if (dartEntry.getValue(DartEntry.IS_LAUNCHABLE) && !dartEntry.getValue(DartEntry.IS_CLIENT)) {
-        sources.add(source);
-//          }
-      }
-    }
-    return sources;
-  }
-
-  @override
-  List<Source> get librarySources => _getSources(SourceKind.LIBRARY);
-
-  /**
-   * Look through the cache for a task that needs to be performed. Return the
-   * task that was found, or `null` if there is no more work to be done.
-   */
-  AnalysisTask get nextAnalysisTask {
-    bool hintsEnabled = _options.hint;
-    bool lintsEnabled = _options.lint;
-    bool hasBlockedTask = false;
-    //
-    // Look for incremental analysis
-    //
-    if (_incrementalAnalysisCache != null &&
-        _incrementalAnalysisCache.hasWork) {
-      AnalysisTask task =
-          new IncrementalAnalysisTask(this, _incrementalAnalysisCache);
-      _incrementalAnalysisCache = null;
-      return task;
-    }
-    //
-    // Look for a source that needs to be analyzed because it has futures
-    // pending.
-    //
-    if (_pendingFutureSources.isNotEmpty) {
-      List<Source> sourcesToRemove = <Source>[];
-      AnalysisTask task;
-      for (Source source in _pendingFutureSources.keys) {
-        SourceEntry sourceEntry = _cache.get(source);
-        List<PendingFuture> pendingFutures = _pendingFutureSources[source];
-        for (int i = 0; i < pendingFutures.length;) {
-          if (pendingFutures[i].evaluate(sourceEntry)) {
-            pendingFutures.removeAt(i);
-          } else {
-            i++;
-          }
-        }
-        if (pendingFutures.isEmpty) {
-          sourcesToRemove.add(source);
-          continue;
-        }
-        AnalysisContextImpl_TaskData taskData = _getNextAnalysisTaskForSource(
-            source, sourceEntry, true, hintsEnabled, lintsEnabled);
-        task = taskData.task;
-        if (task != null) {
-          break;
-        } else if (taskData.isBlocked) {
-          hasBlockedTask = true;
-        } else {
-          // There is no more work to do for this task, so forcibly complete
-          // all its pending futures.
-          for (PendingFuture pendingFuture in pendingFutures) {
-            pendingFuture.forciblyComplete();
-          }
-          sourcesToRemove.add(source);
-        }
-      }
-      for (Source source in sourcesToRemove) {
-        _pendingFutureSources.remove(source);
-      }
-      if (task != null) {
-        return task;
-      }
-    }
-    //
-    // Look for a priority source that needs to be analyzed.
-    //
-    int priorityCount = _priorityOrder.length;
-    for (int i = 0; i < priorityCount; i++) {
-      Source source = _priorityOrder[i];
-      AnalysisContextImpl_TaskData taskData = _getNextAnalysisTaskForSource(
-          source, _cache.get(source), true, hintsEnabled, lintsEnabled);
-      AnalysisTask task = taskData.task;
-      if (task != null) {
-        return task;
-      } else if (taskData.isBlocked) {
-        hasBlockedTask = true;
-      }
-    }
-    if (_neededForResolution != null) {
-      List<Source> sourcesToRemove = new List<Source>();
-      for (Source source in _neededForResolution) {
-        SourceEntry sourceEntry = _cache.get(source);
-        if (sourceEntry is DartEntry) {
-          DartEntry dartEntry = sourceEntry;
-          if (!dartEntry.hasResolvableCompilationUnit) {
-            if (dartEntry.getState(DartEntry.PARSED_UNIT) == CacheState.ERROR) {
-              sourcesToRemove.add(source);
-            } else {
-              AnalysisContextImpl_TaskData taskData =
-                  _createParseDartTask(source, dartEntry);
-              AnalysisTask task = taskData.task;
-              if (task != null) {
-                return task;
-              } else if (taskData.isBlocked) {
-                hasBlockedTask = true;
-              }
-            }
-          }
-        }
-      }
-      int count = sourcesToRemove.length;
-      for (int i = 0; i < count; i++) {
-        _neededForResolution.remove(sourcesToRemove[i]);
-      }
-    }
-    //
-    // Look for a non-priority source that needs to be analyzed.
-    //
-    List<Source> sourcesToRemove = new List<Source>();
-    WorkManager_WorkIterator sources = _workManager.iterator();
-    try {
-      while (sources.hasNext) {
-        Source source = sources.next();
-        AnalysisContextImpl_TaskData taskData = _getNextAnalysisTaskForSource(
-            source, _cache.get(source), false, hintsEnabled, lintsEnabled);
-        AnalysisTask task = taskData.task;
-        if (task != null) {
-          return task;
-        } else if (taskData.isBlocked) {
-          hasBlockedTask = true;
-        } else {
-          sourcesToRemove.add(source);
-        }
-      }
-    } finally {
-      int count = sourcesToRemove.length;
-      for (int i = 0; i < count; i++) {
-        _workManager.remove(sourcesToRemove[i]);
-      }
-    }
-    if (hasBlockedTask) {
-      // All of the analysis work is blocked waiting for an asynchronous task
-      // to complete.
-      return WaitForAsyncTask.instance;
-    }
-    return null;
-  }
-
-  @override
-  Stream<SourcesChangedEvent> get onSourcesChanged =>
-      _onSourcesChangedController.stream;
-
-  /**
-   * Make _pendingFutureSources available to unit tests.
-   */
-  HashMap<Source, List<PendingFuture>> get pendingFutureSources_forTesting =>
-      _pendingFutureSources;
-
-  @override
-  List<Source> get prioritySources => _priorityOrder;
-
-  @override
-  List<AnalysisTarget> get priorityTargets => prioritySources;
-
-  @override
-  CachePartition get privateAnalysisCachePartition => _privatePartition;
-
-  @override
-  SourceFactory get sourceFactory => _sourceFactory;
-
-  @override
-  void set sourceFactory(SourceFactory factory) {
-    if (identical(_sourceFactory, factory)) {
-      return;
-    } else if (factory.context != null) {
-      throw new IllegalStateException(
-          "Source factories cannot be shared between contexts");
-    }
-    if (_sourceFactory != null) {
-      _sourceFactory.context = null;
-    }
-    factory.context = this;
-    _sourceFactory = factory;
-    _coreLibrarySource = _sourceFactory.forUri(DartSdk.DART_CORE);
-    _asyncLibrarySource = _sourceFactory.forUri(DartSdk.DART_ASYNC);
-    _cache = createCacheFromSourceFactory(factory);
-    _invalidateAllLocalResolutionInformation(true);
-  }
-
-  @override
-  List<Source> get sources {
-    List<Source> sources = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      sources.add(iterator.key);
-    }
-    return sources;
-  }
-
-  /**
-   * Return a list of the sources that would be processed by
-   * [performAnalysisTask]. This method duplicates, and must therefore be kept
-   * in sync with, [getNextAnalysisTask]. This method is intended to be used for
-   * testing purposes only.
-   */
-  List<Source> get sourcesNeedingProcessing {
-    HashSet<Source> sources = new HashSet<Source>();
-    bool hintsEnabled = _options.hint;
-    bool lintsEnabled = _options.lint;
-
-    //
-    // Look for priority sources that need to be analyzed.
-    //
-    for (Source source in _priorityOrder) {
-      _getSourcesNeedingProcessing(source, _cache.get(source), true,
-          hintsEnabled, lintsEnabled, sources);
-    }
-    //
-    // Look for non-priority sources that need to be analyzed.
-    //
-    WorkManager_WorkIterator iterator = _workManager.iterator();
-    while (iterator.hasNext) {
-      Source source = iterator.next();
-      _getSourcesNeedingProcessing(source, _cache.get(source), false,
-          hintsEnabled, lintsEnabled, sources);
-    }
-    return new List<Source>.from(sources);
-  }
-
-  @override
-  AnalysisContextStatistics get statistics {
-    AnalysisContextStatisticsImpl statistics =
-        new AnalysisContextStatisticsImpl();
-    visitCacheItems(statistics._internalPutCacheItem);
-    statistics.partitionData = _cache.partitionData;
-    return statistics;
-  }
-
-  IncrementalAnalysisCache get test_incrementalAnalysisCache {
-    return _incrementalAnalysisCache;
-  }
-
-  set test_incrementalAnalysisCache(IncrementalAnalysisCache value) {
-    _incrementalAnalysisCache = value;
-  }
-
-  List<Source> get test_priorityOrder => _priorityOrder;
-
-  @override
-  TypeProvider get typeProvider {
-    if (_typeProvider != null) {
-      return _typeProvider;
-    }
-    Source coreSource = sourceFactory.forUri(DartSdk.DART_CORE);
-    if (coreSource == null) {
-      throw new AnalysisException("Could not create a source for dart:core");
-    }
-    LibraryElement coreElement = computeLibraryElement(coreSource);
-    if (coreElement == null) {
-      throw new AnalysisException("Could not create an element for dart:core");
-    }
-    Source asyncSource = sourceFactory.forUri(DartSdk.DART_ASYNC);
-    if (asyncSource == null) {
-      throw new AnalysisException("Could not create a source for dart:async");
-    }
-    LibraryElement asyncElement = computeLibraryElement(asyncSource);
-    if (asyncElement == null) {
-      throw new AnalysisException("Could not create an element for dart:async");
-    }
-    _typeProvider = new TypeProviderImpl(coreElement, asyncElement);
-    return _typeProvider;
-  }
-
-  /**
-   * Sets the [TypeProvider] for this context.
-   */
-  void set typeProvider(TypeProvider typeProvider) {
-    _typeProvider = typeProvider;
-  }
-
-  @override
-  TypeSystem get typeSystem {
-    if (_typeSystem == null) {
-      _typeSystem = TypeSystem.create(this);
-    }
-    return _typeSystem;
-  }
-
-  @override
-  List<newContext.WorkManager> get workManagers {
-    throw new NotImplementedException('In not task-based AnalysisContext.');
-  }
-
-  @override
-  void addListener(AnalysisListener listener) {
-    if (!_listeners.contains(listener)) {
-      _listeners.add(listener);
-    }
-  }
-
-  @override
-  void applyAnalysisDelta(AnalysisDelta delta) {
-    ChangeSet changeSet = new ChangeSet();
-    delta.analysisLevels.forEach((Source source, AnalysisLevel level) {
-      if (level == AnalysisLevel.NONE) {
-        changeSet.removedSource(source);
-      } else {
-        changeSet.addedSource(source);
-      }
-    });
-    applyChanges(changeSet);
-  }
-
-  @override
-  ApplyChangesStatus applyChanges(ChangeSet changeSet) {
-    if (changeSet.isEmpty) {
-      return new ApplyChangesStatus(false);
-    }
-    //
-    // First, compute the list of sources that have been removed.
-    //
-    List<Source> removedSources =
-        new List<Source>.from(changeSet.removedSources);
-    for (SourceContainer container in changeSet.removedContainers) {
-      _addSourcesInContainer(removedSources, container);
-    }
-    //
-    // Then determine which cached results are no longer valid.
-    //
-    for (Source source in changeSet.addedSources) {
-      _sourceAvailable(source);
-    }
-    for (Source source in changeSet.changedSources) {
-      if (_contentCache.getContents(source) != null) {
-        // This source is overridden in the content cache, so the change will
-        // have no effect. Just ignore it to avoid wasting time doing
-        // re-analysis.
-        continue;
-      }
-      _sourceChanged(source);
-    }
-    changeSet.changedContents.forEach((Source key, String value) {
-      _contentsChanged(key, value, false);
-    });
-    changeSet.changedRanges
-        .forEach((Source source, ChangeSet_ContentChange change) {
-      _contentRangeChanged(source, change.contents, change.offset,
-          change.oldLength, change.newLength);
-    });
-    for (Source source in changeSet.deletedSources) {
-      _sourceDeleted(source);
-    }
-    for (Source source in removedSources) {
-      _sourceRemoved(source);
-    }
-    _onSourcesChangedController.add(new SourcesChangedEvent(changeSet));
-    return new ApplyChangesStatus(true);
-  }
-
-  @override
-  String computeDocumentationComment(Element element) {
-    if (element == null) {
-      return null;
-    }
-    Source source = element.source;
-    if (source == null) {
-      return null;
-    }
-    SourceRange docRange = element.docRange;
-    if (docRange == null) {
-      return null;
-    }
-    String code = getContents(source).data;
-    String comment = code.substring(docRange.offset, docRange.end);
-    return comment.replaceAll('\r\n', '\n');
-  }
-
-  @override
-  List<AnalysisError> computeErrors(Source source) {
-    bool enableHints = _options.hint;
-    bool enableLints = _options.lint;
-
-    SourceEntry sourceEntry = _getReadableSourceEntry(source);
-    if (sourceEntry is DartEntry) {
-      List<AnalysisError> errors = new List<AnalysisError>();
-      try {
-        DartEntry dartEntry = sourceEntry;
-        ListUtilities.addAll(
-            errors, _getDartScanData(source, dartEntry, DartEntry.SCAN_ERRORS));
-        dartEntry = _getReadableDartEntry(source);
-        ListUtilities.addAll(errors,
-            _getDartParseData(source, dartEntry, DartEntry.PARSE_ERRORS));
-        dartEntry = _getReadableDartEntry(source);
-        if (dartEntry.getValue(DartEntry.SOURCE_KIND) == SourceKind.LIBRARY) {
-          ListUtilities.addAll(
-              errors,
-              _getDartResolutionData(
-                  source, source, dartEntry, DartEntry.RESOLUTION_ERRORS));
-          dartEntry = _getReadableDartEntry(source);
-          ListUtilities.addAll(
-              errors,
-              _getDartVerificationData(
-                  source, source, dartEntry, DartEntry.VERIFICATION_ERRORS));
-          if (enableHints) {
-            dartEntry = _getReadableDartEntry(source);
-            ListUtilities.addAll(errors,
-                _getDartHintData(source, source, dartEntry, DartEntry.HINTS));
-          }
-          if (enableLints) {
-            dartEntry = _getReadableDartEntry(source);
-            ListUtilities.addAll(errors,
-                _getDartLintData(source, source, dartEntry, DartEntry.LINTS));
-          }
-        } else {
-          List<Source> libraries = getLibrariesContaining(source);
-          for (Source librarySource in libraries) {
-            ListUtilities.addAll(
-                errors,
-                _getDartResolutionData(source, librarySource, dartEntry,
-                    DartEntry.RESOLUTION_ERRORS));
-            dartEntry = _getReadableDartEntry(source);
-            ListUtilities.addAll(
-                errors,
-                _getDartVerificationData(source, librarySource, dartEntry,
-                    DartEntry.VERIFICATION_ERRORS));
-            if (enableHints) {
-              dartEntry = _getReadableDartEntry(source);
-              ListUtilities.addAll(
-                  errors,
-                  _getDartHintData(
-                      source, librarySource, dartEntry, DartEntry.HINTS));
-            }
-            if (enableLints) {
-              dartEntry = _getReadableDartEntry(source);
-              ListUtilities.addAll(
-                  errors,
-                  _getDartLintData(
-                      source, librarySource, dartEntry, DartEntry.LINTS));
-            }
-          }
-        }
-      } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-        AnalysisEngine.instance.logger.logInformation(
-            "Could not compute errors",
-            new CaughtException(exception, stackTrace));
-      }
-      if (errors.isEmpty) {
-        return AnalysisError.NO_ERRORS;
-      }
-      return errors;
-    } else if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      try {
-        return _getHtmlResolutionData2(
-            source, htmlEntry, HtmlEntry.RESOLUTION_ERRORS);
-      } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-        AnalysisEngine.instance.logger.logInformation(
-            "Could not compute errors",
-            new CaughtException(exception, stackTrace));
-      }
-    }
-    return AnalysisError.NO_ERRORS;
-  }
-
-  @override
-  List<Source> computeExportedLibraries(Source source) => _getDartParseData2(
-      source, DartEntry.EXPORTED_LIBRARIES, Source.EMPTY_LIST);
-
-  @override
-  @deprecated
-  HtmlElement computeHtmlElement(Source source) =>
-      _getHtmlResolutionData(source, HtmlEntry.ELEMENT, null);
-
-  @override
-  List<Source> computeImportedLibraries(Source source) => _getDartParseData2(
-      source, DartEntry.IMPORTED_LIBRARIES, Source.EMPTY_LIST);
-
-  @override
-  SourceKind computeKindOf(Source source) {
-    SourceEntry sourceEntry = _getReadableSourceEntry(source);
-    if (sourceEntry == null) {
-      return SourceKind.UNKNOWN;
-    } else if (sourceEntry is DartEntry) {
-      try {
-        return _getDartParseData(source, sourceEntry, DartEntry.SOURCE_KIND);
-      } on AnalysisException {
-        return SourceKind.UNKNOWN;
-      }
-    }
-    return sourceEntry.kind;
-  }
-
-  @override
-  LibraryElement computeLibraryElement(Source source) =>
-      _getDartResolutionData2(source, source, DartEntry.ELEMENT, null);
-
-  @override
-  LineInfo computeLineInfo(Source source) {
-    SourceEntry sourceEntry = _getReadableSourceEntry(source);
-    try {
-      if (sourceEntry is HtmlEntry) {
-        return _getHtmlParseData(source, SourceEntry.LINE_INFO, null);
-      } else if (sourceEntry is DartEntry) {
-        return _getDartScanData2(source, SourceEntry.LINE_INFO, null);
-      }
-    } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logInformation(
-          "Could not compute ${SourceEntry.LINE_INFO}",
-          new CaughtException(exception, stackTrace));
-    }
-    return null;
-  }
-
-  @override
-  CompilationUnit computeResolvableCompilationUnit(Source source) {
-    DartEntry dartEntry = _getReadableDartEntry(source);
-    if (dartEntry == null) {
-      throw new AnalysisException(
-          "computeResolvableCompilationUnit for non-Dart: ${source.fullName}");
-    }
-    dartEntry = _cacheDartParseData(source, dartEntry, DartEntry.PARSED_UNIT);
-    CompilationUnit unit = dartEntry.resolvableCompilationUnit;
-    if (unit == null) {
-      throw new AnalysisException(
-          "Internal error: computeResolvableCompilationUnit could not parse ${source.fullName}",
-          new CaughtException(dartEntry.exception, null));
-    }
-    return unit;
-  }
-
-  @override
-  CancelableFuture<CompilationUnit> computeResolvedCompilationUnitAsync(
-      Source unitSource, Source librarySource) {
-    return new _AnalysisFutureHelper<CompilationUnit>(this)
-        .computeAsync(unitSource, (SourceEntry sourceEntry) {
-      if (sourceEntry is DartEntry) {
-        if (sourceEntry.getStateInLibrary(
-                DartEntry.RESOLVED_UNIT, librarySource) ==
-            CacheState.ERROR) {
-          throw sourceEntry.exception;
-        }
-        return sourceEntry.getValueInLibrary(
-            DartEntry.RESOLVED_UNIT, librarySource);
-      }
-      throw new AnalysisNotScheduledError();
-    });
-  }
-
-  @override
-  Object computeResult(AnalysisTarget target, ResultDescriptor result) {
-    return result.defaultValue;
-  }
-
-  /**
-   * Create an analysis cache based on the given source [factory].
-   */
-  AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
-    if (factory == null) {
-      return new AnalysisCache(<CachePartition>[_privatePartition]);
-    }
-    DartSdk sdk = factory.dartSdk;
-    if (sdk == null) {
-      return new AnalysisCache(<CachePartition>[_privatePartition]);
-    }
-    return new AnalysisCache(<CachePartition>[
-      AnalysisEngine.instance.partitionManager.forSdk(sdk),
-      _privatePartition
-    ]);
-  }
-
-  @override
-  void dispose() {
-    _disposed = true;
-    for (List<PendingFuture> pendingFutures in _pendingFutureSources.values) {
-      for (PendingFuture pendingFuture in pendingFutures) {
-        pendingFuture.forciblyComplete();
-      }
-    }
-    _pendingFutureSources.clear();
-  }
-
-  @override
-  List<CompilationUnit> ensureResolvedDartUnits(Source unitSource) {
-    SourceEntry sourceEntry = _cache.get(unitSource);
-    if (sourceEntry is! DartEntry) {
-      return null;
-    }
-    DartEntry dartEntry = sourceEntry;
-    // Check every library.
-    List<CompilationUnit> units = <CompilationUnit>[];
-    List<Source> containingLibraries = dartEntry.containingLibraries;
-    for (Source librarySource in containingLibraries) {
-      CompilationUnit unit =
-          dartEntry.getValueInLibrary(DartEntry.RESOLVED_UNIT, librarySource);
-      if (unit == null) {
-        units = null;
-        break;
-      }
-      units.add(unit);
-    }
-    // Invalidate the flushed RESOLVED_UNIT to force it eventually.
-    if (units == null) {
-      bool shouldBeScheduled = false;
-      for (Source librarySource in containingLibraries) {
-        if (dartEntry.getStateInLibrary(
-                DartEntry.RESOLVED_UNIT, librarySource) ==
-            CacheState.FLUSHED) {
-          dartEntry.setStateInLibrary(
-              DartEntry.RESOLVED_UNIT, librarySource, CacheState.INVALID);
-          shouldBeScheduled = true;
-        }
-      }
-      if (shouldBeScheduled) {
-        _workManager.add(unitSource, SourcePriority.UNKNOWN);
-      }
-      // We cannot provide resolved units right now,
-      // but the future analysis will.
-      return null;
-    }
-    // done
-    return units;
-  }
-
-  @override
-  bool exists(Source source) {
-    if (source == null) {
-      return false;
-    }
-    if (_contentCache.getContents(source) != null) {
-      return true;
-    }
-    return source.exists();
-  }
-
-  @override
-  cache.CacheEntry getCacheEntry(AnalysisTarget target) {
-    return null;
-  }
-
-  @override
-  CompilationUnitElement getCompilationUnitElement(
-      Source unitSource, Source librarySource) {
-    LibraryElement libraryElement = getLibraryElement(librarySource);
-    if (libraryElement != null) {
-      // try defining unit
-      CompilationUnitElement definingUnit =
-          libraryElement.definingCompilationUnit;
-      if (definingUnit.source == unitSource) {
-        return definingUnit;
-      }
-      // try parts
-      for (CompilationUnitElement partUnit in libraryElement.parts) {
-        if (partUnit.source == unitSource) {
-          return partUnit;
-        }
-      }
-    }
-    return null;
-  }
-
-  @override
-  Object getConfigurationData(ResultDescriptor key) => _configurationData[key];
-
-  @override
-  TimestampedData<String> getContents(Source source) {
-    String contents = _contentCache.getContents(source);
-    if (contents != null) {
-      return new TimestampedData<String>(
-          _contentCache.getModificationStamp(source), contents);
-    }
-    return source.contents;
-  }
-
-  @override
-  InternalAnalysisContext getContextFor(Source source) {
-    InternalAnalysisContext context = _cache.getContextFor(source);
-    return context == null ? this : context;
-  }
-
-  @override
-  Element getElement(ElementLocation location) {
-    // TODO(brianwilkerson) This should not be a "get" method.
-    try {
-      List<String> components = location.components;
-      Source source = _computeSourceFromEncoding(components[0]);
-      String sourceName = source.shortName;
-      if (AnalysisEngine.isDartFileName(sourceName)) {
-        ElementImpl element = computeLibraryElement(source) as ElementImpl;
-        for (int i = 1; i < components.length; i++) {
-          if (element == null) {
-            return null;
-          }
-          element = element.getChild(components[i]);
-        }
-        return element;
-      }
-      if (AnalysisEngine.isHtmlFileName(sourceName)) {
-        return computeHtmlElement(source);
-      }
-    } catch (exception) {
-      // If the location cannot be decoded for some reason then the underlying
-      // cause should have been logged already and we can fall though to return
-      // null.
-    }
-    return null;
-  }
-
-  @override
-  AnalysisErrorInfo getErrors(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      return new AnalysisErrorInfoImpl(
-          dartEntry.allErrors, dartEntry.getValue(SourceEntry.LINE_INFO));
-    } else if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      return new AnalysisErrorInfoImpl(
-          htmlEntry.allErrors, htmlEntry.getValue(SourceEntry.LINE_INFO));
-    }
-    return new AnalysisErrorInfoImpl(AnalysisError.NO_ERRORS, null);
-  }
-
-  @override
-  @deprecated
-  HtmlElement getHtmlElement(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry is HtmlEntry) {
-      return sourceEntry.getValue(HtmlEntry.ELEMENT);
-    }
-    return null;
-  }
-
-  @override
-  List<Source> getHtmlFilesReferencing(Source source) {
-    SourceKind sourceKind = getKindOf(source);
-    if (sourceKind == null) {
-      return Source.EMPTY_LIST;
-    }
-    List<Source> htmlSources = new List<Source>();
-    while (true) {
-      if (sourceKind == SourceKind.PART) {
-        List<Source> librarySources = getLibrariesContaining(source);
-        MapIterator<Source, SourceEntry> partIterator = _cache.iterator();
-        while (partIterator.moveNext()) {
-          SourceEntry sourceEntry = partIterator.value;
-          if (sourceEntry.kind == SourceKind.HTML) {
-            List<Source> referencedLibraries = (sourceEntry as HtmlEntry)
-                .getValue(HtmlEntry.REFERENCED_LIBRARIES);
-            if (_containsAny(referencedLibraries, librarySources)) {
-              htmlSources.add(partIterator.key);
-            }
-          }
-        }
-      } else {
-        MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-        while (iterator.moveNext()) {
-          SourceEntry sourceEntry = iterator.value;
-          if (sourceEntry.kind == SourceKind.HTML) {
-            List<Source> referencedLibraries = (sourceEntry as HtmlEntry)
-                .getValue(HtmlEntry.REFERENCED_LIBRARIES);
-            if (_contains(referencedLibraries, source)) {
-              htmlSources.add(iterator.key);
-            }
-          }
-        }
-      }
-      break;
-    }
-    if (htmlSources.isEmpty) {
-      return Source.EMPTY_LIST;
-    }
-    return htmlSources;
-  }
-
-  @override
-  SourceKind getKindOf(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry == null) {
-      return SourceKind.UNKNOWN;
-    }
-    return sourceEntry.kind;
-  }
-
-  @override
-  List<Source> getLibrariesContaining(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry is DartEntry) {
-      return sourceEntry.containingLibraries;
-    }
-    return Source.EMPTY_LIST;
-  }
-
-  @override
-  List<Source> getLibrariesDependingOn(Source librarySource) {
-    List<Source> dependentLibraries = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      SourceEntry sourceEntry = iterator.value;
-      if (sourceEntry.kind == SourceKind.LIBRARY) {
-        if (_contains(
-            (sourceEntry as DartEntry).getValue(DartEntry.EXPORTED_LIBRARIES),
-            librarySource)) {
-          dependentLibraries.add(iterator.key);
-        }
-        if (_contains(
-            (sourceEntry as DartEntry).getValue(DartEntry.IMPORTED_LIBRARIES),
-            librarySource)) {
-          dependentLibraries.add(iterator.key);
-        }
-      }
-    }
-    if (dependentLibraries.isEmpty) {
-      return Source.EMPTY_LIST;
-    }
-    return dependentLibraries;
-  }
-
-  @override
-  List<Source> getLibrariesReferencedFromHtml(Source htmlSource) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(htmlSource);
-    if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      return htmlEntry.getValue(HtmlEntry.REFERENCED_LIBRARIES);
-    }
-    return Source.EMPTY_LIST;
-  }
-
-  @override
-  LibraryElement getLibraryElement(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry is DartEntry) {
-      return sourceEntry.getValue(DartEntry.ELEMENT);
-    }
-    return null;
-  }
-
-  @override
-  LineInfo getLineInfo(Source source) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(source);
-    if (sourceEntry != null) {
-      return sourceEntry.getValue(SourceEntry.LINE_INFO);
-    }
-    return null;
-  }
-
-  @override
-  int getModificationStamp(Source source) {
-    int stamp = _contentCache.getModificationStamp(source);
-    if (stamp != null) {
-      return stamp;
-    }
-    return source.modificationStamp;
-  }
-
-  @override
-  ChangeNoticeImpl getNotice(Source source) {
-    ChangeNoticeImpl notice = _pendingNotices[source];
-    if (notice == null) {
-      notice = new ChangeNoticeImpl(source);
-      _pendingNotices[source] = notice;
-    }
-    return notice;
-  }
-
-  @override
-  Namespace getPublicNamespace(LibraryElement library) {
-    // TODO(brianwilkerson) Rename this to not start with 'get'.
-    // Note that this is not part of the API of the interface.
-    Source source = library.definingCompilationUnit.source;
-    DartEntry dartEntry = _getReadableDartEntry(source);
-    if (dartEntry == null) {
-      return null;
-    }
-    Namespace namespace = null;
-    if (identical(dartEntry.getValue(DartEntry.ELEMENT), library)) {
-      namespace = dartEntry.getValue(DartEntry.PUBLIC_NAMESPACE);
-    }
-    if (namespace == null) {
-      NamespaceBuilder builder = new NamespaceBuilder();
-      namespace = builder.createPublicNamespaceForLibrary(library);
-      if (dartEntry == null) {
-        AnalysisEngine.instance.logger.logError(
-            "Could not compute the public namespace for ${library.source.fullName}",
-            new CaughtException(
-                new AnalysisException(
-                    "A Dart file became a non-Dart file: ${source.fullName}"),
-                null));
-        return null;
-      }
-      if (identical(dartEntry.getValue(DartEntry.ELEMENT), library)) {
-        dartEntry.setValue(DartEntry.PUBLIC_NAMESPACE, namespace);
-      }
-    }
-    return namespace;
-  }
-
-  /**
-   * Return the cache entry associated with the given [source], or `null` if
-   * there is no entry associated with the source.
-   */
-  SourceEntry getReadableSourceEntryOrNull(Source source) => _cache.get(source);
-
-  @override
-  CompilationUnit getResolvedCompilationUnit(
-      Source unitSource, LibraryElement library) {
-    if (library == null) {
-      return null;
-    }
-    return getResolvedCompilationUnit2(unitSource, library.source);
-  }
-
-  @override
-  CompilationUnit getResolvedCompilationUnit2(
-      Source unitSource, Source librarySource) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(unitSource);
-    if (sourceEntry is DartEntry) {
-      return sourceEntry.getValueInLibrary(
-          DartEntry.RESOLVED_UNIT, librarySource);
-    }
-    return null;
-  }
-
-  @override
-  @deprecated
-  ht.HtmlUnit getResolvedHtmlUnit(Source htmlSource) {
-    SourceEntry sourceEntry = getReadableSourceEntryOrNull(htmlSource);
-    if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      return htmlEntry.getValue(HtmlEntry.RESOLVED_UNIT);
-    }
-    return null;
-  }
-
-  @override
-  Object getResult(AnalysisTarget target, ResultDescriptor result) {
-    return result.defaultValue;
-  }
-
-  @override
-  List<Source> getSourcesWithFullName(String path) {
-    List<Source> sources = <Source>[];
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      if (iterator.key.fullName == path) {
-        sources.add(iterator.key);
-      }
-    }
-    return sources;
-  }
-
-  @override
-  bool handleContentsChanged(
-      Source source, String originalContents, String newContents, bool notify) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry == null) {
-      return false;
-    }
-    bool changed = newContents != originalContents;
-    if (newContents != null) {
-      if (changed) {
-        _incrementalAnalysisCache =
-            IncrementalAnalysisCache.clear(_incrementalAnalysisCache, source);
-        if (!analysisOptions.incremental ||
-            !_tryPoorMansIncrementalResolution(source, newContents)) {
-          _sourceChanged(source);
-        }
-        sourceEntry.modificationTime =
-            _contentCache.getModificationStamp(source);
-        sourceEntry.setValue(SourceEntry.CONTENT, newContents);
-      } else {
-        sourceEntry.modificationTime =
-            _contentCache.getModificationStamp(source);
-      }
-    } else if (originalContents != null) {
-      _incrementalAnalysisCache =
-          IncrementalAnalysisCache.clear(_incrementalAnalysisCache, source);
-      // We are removing the overlay for the file, check if the file's
-      // contents is the same as it was in the overlay.
-      try {
-        TimestampedData<String> fileContents = getContents(source);
-        newContents = fileContents.data;
-        sourceEntry.modificationTime = fileContents.modificationTime;
-        if (newContents == originalContents) {
-          sourceEntry.setValue(SourceEntry.CONTENT, newContents);
-          changed = false;
-        }
-      } catch (e) {}
-      // If not the same content (e.g. the file is being closed without save),
-      // then force analysis.
-      if (changed) {
-        if (!analysisOptions.incremental ||
-            !_tryPoorMansIncrementalResolution(source, newContents)) {
-          _sourceChanged(source);
-        }
-      }
-    }
-    if (notify && changed) {
-      _onSourcesChangedController
-          .add(new SourcesChangedEvent.changedContent(source, newContents));
-    }
-    return changed;
-  }
-
-  @override
-  void invalidateLibraryHints(Source librarySource) {
-    SourceEntry sourceEntry = _cache.get(librarySource);
-    if (sourceEntry is! DartEntry) {
-      return;
-    }
-    DartEntry dartEntry = sourceEntry;
-    // Prepare sources to invalidate hints in.
-    List<Source> sources = <Source>[librarySource];
-    sources.addAll(dartEntry.getValue(DartEntry.INCLUDED_PARTS));
-    // Invalidate hints and lints.
-    for (Source source in sources) {
-      DartEntry dartEntry = _cache.get(source);
-      if (dartEntry.getStateInLibrary(DartEntry.HINTS, librarySource) ==
-          CacheState.VALID) {
-        dartEntry.setStateInLibrary(
-            DartEntry.HINTS, librarySource, CacheState.INVALID);
-      }
-      if (dartEntry.getStateInLibrary(DartEntry.LINTS, librarySource) ==
-          CacheState.VALID) {
-        dartEntry.setStateInLibrary(
-            DartEntry.LINTS, librarySource, CacheState.INVALID);
-      }
-    }
-  }
-
-  @override
-  bool isClientLibrary(Source librarySource) {
-    SourceEntry sourceEntry = _getReadableSourceEntry(librarySource);
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      return dartEntry.getValue(DartEntry.IS_CLIENT) &&
-          dartEntry.getValue(DartEntry.IS_LAUNCHABLE);
-    }
-    return false;
-  }
-
-  @override
-  bool isServerLibrary(Source librarySource) {
-    SourceEntry sourceEntry = _getReadableSourceEntry(librarySource);
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      return !dartEntry.getValue(DartEntry.IS_CLIENT) &&
-          dartEntry.getValue(DartEntry.IS_LAUNCHABLE);
-    }
-    return false;
-  }
-
-  @override
-  Stream<ComputedResult> onResultComputed(ResultDescriptor descriptor) {
-    throw new NotImplementedException('In not task-based AnalysisContext.');
-  }
-
-  @override
-  CompilationUnit parseCompilationUnit(Source source) =>
-      _getDartParseData2(source, DartEntry.PARSED_UNIT, null);
-
-  @override
-  Document parseHtmlDocument(Source source) {
-    return null;
-  }
-
-  @override
-  @deprecated
-  ht.HtmlUnit parseHtmlUnit(Source source) =>
-      _getHtmlParseData(source, HtmlEntry.PARSED_UNIT, null);
-
-  @override
-  AnalysisResult performAnalysisTask() {
-    if (_TRACE_PERFORM_TASK) {
-      print("----------------------------------------");
-    }
-    return PerformanceStatistics.performAnaysis.makeCurrentWhile(() {
-      int getStart = JavaSystem.currentTimeMillis();
-      AnalysisTask task = PerformanceStatistics.nextTask
-          .makeCurrentWhile(() => nextAnalysisTask);
-      int getEnd = JavaSystem.currentTimeMillis();
-      if (task == null) {
-        _validateLastIncrementalResolutionResult();
-        if (_performAnalysisTaskStopwatch != null) {
-          AnalysisEngine.instance.instrumentationService.logPerformance(
-              AnalysisPerformanceKind.FULL,
-              _performAnalysisTaskStopwatch,
-              'context_id=$_id');
-          _performAnalysisTaskStopwatch = null;
-        }
-        return new AnalysisResult(
-            _getChangeNotices(true), getEnd - getStart, null, -1);
-      }
-      if (_performAnalysisTaskStopwatch == null) {
-        _performAnalysisTaskStopwatch = new Stopwatch()..start();
-      }
-      String taskDescription = task.toString();
-      _notifyAboutToPerformTask(taskDescription);
-      if (_TRACE_PERFORM_TASK) {
-        print(taskDescription);
-      }
-      int performStart = JavaSystem.currentTimeMillis();
-      try {
-        task.perform(_resultRecorder);
-      } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-        AnalysisEngine.instance.logger.logInformation(
-            "Could not perform analysis task: $taskDescription",
-            new CaughtException(exception, stackTrace));
-      } on AnalysisException catch (exception, stackTrace) {
-        if (exception.cause is! JavaIOException) {
-          AnalysisEngine.instance.logger.logError(
-              "Internal error while performing the task: $task",
-              new CaughtException(exception, stackTrace));
-        }
-      }
-      int performEnd = JavaSystem.currentTimeMillis();
-      List<ChangeNotice> notices = _getChangeNotices(false);
-      int noticeCount = notices.length;
-      for (int i = 0; i < noticeCount; i++) {
-        ChangeNotice notice = notices[i];
-        Source source = notice.source;
-        // TODO(brianwilkerson) Figure out whether the compilation unit is
-        // always resolved, or whether we need to decide whether to invoke the
-        // "parsed" or "resolved" method. This might be better done when
-        // recording task results in order to reduce the chance of errors.
-//        if (notice.getCompilationUnit() != null) {
-//          notifyResolvedDart(source, notice.getCompilationUnit());
-//        } else if (notice.getHtmlUnit() != null) {
-//          notifyResolvedHtml(source, notice.getHtmlUnit());
-//        }
-        _notifyErrors(source, notice.errors, notice.lineInfo);
-      }
-      return new AnalysisResult(notices, getEnd - getStart,
-          task.runtimeType.toString(), performEnd - performStart);
-    });
-  }
-
-  @override
-  void recordLibraryElements(Map<Source, LibraryElement> elementMap) {
-    Source htmlSource = _sourceFactory.forUri(DartSdk.DART_HTML);
-    elementMap.forEach((Source librarySource, LibraryElement library) {
-      //
-      // Cache the element in the library's info.
-      //
-      DartEntry dartEntry = _getReadableDartEntry(librarySource);
-      if (dartEntry != null) {
-        _recordElementData(dartEntry, library, library.source, htmlSource);
-        dartEntry.setState(SourceEntry.CONTENT, CacheState.FLUSHED);
-        dartEntry.setValue(SourceEntry.LINE_INFO, new LineInfo(<int>[0]));
-        // DartEntry.ELEMENT - set in recordElementData
-        dartEntry.setValue(DartEntry.EXPORTED_LIBRARIES, Source.EMPTY_LIST);
-        dartEntry.setValue(DartEntry.IMPORTED_LIBRARIES, Source.EMPTY_LIST);
-        dartEntry.setValue(DartEntry.INCLUDED_PARTS, Source.EMPTY_LIST);
-        // DartEntry.IS_CLIENT - set in recordElementData
-        // DartEntry.IS_LAUNCHABLE - set in recordElementData
-        dartEntry.setValue(DartEntry.PARSE_ERRORS, AnalysisError.NO_ERRORS);
-        dartEntry.setState(DartEntry.PARSED_UNIT, CacheState.FLUSHED);
-        dartEntry.setState(DartEntry.PUBLIC_NAMESPACE, CacheState.FLUSHED);
-        dartEntry.setValue(DartEntry.SCAN_ERRORS, AnalysisError.NO_ERRORS);
-        dartEntry.setValue(DartEntry.SOURCE_KIND, SourceKind.LIBRARY);
-        dartEntry.setState(DartEntry.TOKEN_STREAM, CacheState.FLUSHED);
-        dartEntry.setValueInLibrary(DartEntry.RESOLUTION_ERRORS, librarySource,
-            AnalysisError.NO_ERRORS);
-        dartEntry.setStateInLibrary(
-            DartEntry.RESOLVED_UNIT, librarySource, CacheState.FLUSHED);
-        dartEntry.setValueInLibrary(DartEntry.VERIFICATION_ERRORS,
-            librarySource, AnalysisError.NO_ERRORS);
-        dartEntry.setValueInLibrary(
-            DartEntry.HINTS, librarySource, AnalysisError.NO_ERRORS);
-        dartEntry.setValueInLibrary(
-            DartEntry.LINTS, librarySource, AnalysisError.NO_ERRORS);
-      }
-    });
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry recordResolveDartLibraryCycleTaskResults(
-      ResolveDartLibraryCycleTask task) {
-    LibraryResolver2 resolver = task.libraryResolver;
-    CaughtException thrownException = task.exception;
-    Source unitSource = task.unitSource;
-    DartEntry unitEntry = _getReadableDartEntry(unitSource);
-    if (resolver != null) {
-      //
-      // The resolver should only be null if an exception was thrown before (or
-      // while) it was being created.
-      //
-      List<ResolvableLibrary> resolvedLibraries = resolver.resolvedLibraries;
-      if (resolvedLibraries == null) {
-        //
-        // The resolved libraries should only be null if an exception was thrown
-        // during resolution.
-        //
-        if (thrownException == null) {
-          var message = "In recordResolveDartLibraryCycleTaskResults, "
-              "resolvedLibraries was null and there was no thrown exception";
-          unitEntry.recordResolutionError(
-              new CaughtException(new AnalysisException(message), null));
-        } else {
-          unitEntry.recordResolutionError(thrownException);
-        }
-        _removeFromCache(unitSource);
-        if (thrownException != null) {
-          throw new AnalysisException('<rethrow>', thrownException);
-        }
-        return unitEntry;
-      }
-      Source htmlSource = sourceFactory.forUri(DartSdk.DART_HTML);
-      RecordingErrorListener errorListener = resolver.errorListener;
-      for (ResolvableLibrary library in resolvedLibraries) {
-        Source librarySource = library.librarySource;
-        for (Source source in library.compilationUnitSources) {
-          CompilationUnit unit = library.getAST(source);
-          List<AnalysisError> errors = errorListener.getErrorsForSource(source);
-          LineInfo lineInfo = getLineInfo(source);
-          DartEntry dartEntry = _cache.get(source);
-          if (thrownException == null) {
-            dartEntry.setState(DartEntry.PARSED_UNIT, CacheState.FLUSHED);
-            dartEntry.setValueInLibrary(
-                DartEntry.RESOLVED_UNIT, librarySource, unit);
-            dartEntry.setValueInLibrary(
-                DartEntry.RESOLUTION_ERRORS, librarySource, errors);
-            if (source == librarySource) {
-              _recordElementData(
-                  dartEntry, library.libraryElement, librarySource, htmlSource);
-            }
-            _cache.storedAst(source);
-          } else {
-            dartEntry.recordResolutionErrorInLibrary(
-                librarySource, thrownException);
-          }
-          if (source != librarySource) {
-            _workManager.add(source, SourcePriority.PRIORITY_PART);
-          }
-          ChangeNoticeImpl notice = getNotice(source);
-          notice.resolvedDartUnit = unit;
-          notice.setErrors(dartEntry.allErrors, lineInfo);
-        }
-      }
-    }
-    if (thrownException != null) {
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    return unitEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry recordResolveDartLibraryTaskResults(ResolveDartLibraryTask task) {
-    LibraryResolver resolver = task.libraryResolver;
-    CaughtException thrownException = task.exception;
-    Source unitSource = task.unitSource;
-    DartEntry unitEntry = _getReadableDartEntry(unitSource);
-    if (resolver != null) {
-      //
-      // The resolver should only be null if an exception was thrown before (or
-      // while) it was being created.
-      //
-      Set<Library> resolvedLibraries = resolver.resolvedLibraries;
-      if (resolvedLibraries == null) {
-        //
-        // The resolved libraries should only be null if an exception was thrown
-        // during resolution.
-        //
-        if (thrownException == null) {
-          String message = "In recordResolveDartLibraryTaskResults, "
-              "resolvedLibraries was null and there was no thrown exception";
-          unitEntry.recordResolutionError(
-              new CaughtException(new AnalysisException(message), null));
-        } else {
-          unitEntry.recordResolutionError(thrownException);
-        }
-        _removeFromCache(unitSource);
-        if (thrownException != null) {
-          throw new AnalysisException('<rethrow>', thrownException);
-        }
-        return unitEntry;
-      }
-      Source htmlSource = sourceFactory.forUri(DartSdk.DART_HTML);
-      RecordingErrorListener errorListener = resolver.errorListener;
-      for (Library library in resolvedLibraries) {
-        Source librarySource = library.librarySource;
-        for (Source source in library.compilationUnitSources) {
-          CompilationUnit unit = library.getAST(source);
-          List<AnalysisError> errors = errorListener.getErrorsForSource(source);
-          LineInfo lineInfo = getLineInfo(source);
-          DartEntry dartEntry = _cache.get(source);
-          if (thrownException == null) {
-            dartEntry.setValue(SourceEntry.LINE_INFO, lineInfo);
-            dartEntry.setState(DartEntry.PARSED_UNIT, CacheState.FLUSHED);
-            dartEntry.setValueInLibrary(
-                DartEntry.RESOLVED_UNIT, librarySource, unit);
-            dartEntry.setValueInLibrary(
-                DartEntry.RESOLUTION_ERRORS, librarySource, errors);
-            if (source == librarySource) {
-              _recordElementData(
-                  dartEntry, library.libraryElement, librarySource, htmlSource);
-            }
-            _cache.storedAst(source);
-          } else {
-            dartEntry.recordResolutionErrorInLibrary(
-                librarySource, thrownException);
-            _removeFromCache(source);
-          }
-          if (source != librarySource) {
-            _workManager.add(source, SourcePriority.PRIORITY_PART);
-          }
-          ChangeNoticeImpl notice = getNotice(source);
-          notice.resolvedDartUnit = unit;
-          notice.setErrors(dartEntry.allErrors, lineInfo);
-        }
-      }
-    }
-    if (thrownException != null) {
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    return unitEntry;
-  }
-
-  @override
-  void removeListener(AnalysisListener listener) {
-    _listeners.remove(listener);
-  }
-
-  @override
-  CompilationUnit resolveCompilationUnit(
-      Source unitSource, LibraryElement library) {
-    if (library == null) {
-      return null;
-    }
-    return resolveCompilationUnit2(unitSource, library.source);
-  }
-
-  @override
-  CompilationUnit resolveCompilationUnit2(
-          Source unitSource, Source librarySource) =>
-      _getDartResolutionData2(
-          unitSource, librarySource, DartEntry.RESOLVED_UNIT, null);
-
-  @override
-  @deprecated
-  ht.HtmlUnit resolveHtmlUnit(Source htmlSource) {
-    computeHtmlElement(htmlSource);
-    return parseHtmlUnit(htmlSource);
-  }
-
-  @override
-  void setChangedContents(Source source, String contents, int offset,
-      int oldLength, int newLength) {
-    if (_contentRangeChanged(source, contents, offset, oldLength, newLength)) {
-      _onSourcesChangedController.add(new SourcesChangedEvent.changedRange(
-          source, contents, offset, oldLength, newLength));
-    }
-  }
-
-  @override
-  void setConfigurationData(ResultDescriptor key, Object data) {
-    _configurationData[key] = data;
-  }
-
-  @override
-  void setContents(Source source, String contents) {
-    _contentsChanged(source, contents, true);
-  }
-
-  @override
-  bool shouldErrorsBeAnalyzed(Source source, Object entry) {
-    DartEntry dartEntry = entry;
-    if (source.isInSystemLibrary) {
-      return _generateSdkErrors;
-    } else if (!dartEntry.explicitlyAdded) {
-      return _generateImplicitErrors;
-    } else {
-      return true;
-    }
-  }
-
-  @override
-  void test_flushAstStructures(Source source) {
-    DartEntry dartEntry = getReadableSourceEntryOrNull(source);
-    dartEntry.flushAstStructures();
-  }
-
-  @override
-  bool validateCacheConsistency() {
-    int consistencyCheckStart = JavaSystem.nanoTime();
-    List<Source> changedSources = new List<Source>();
-    List<Source> missingSources = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      SourceEntry sourceEntry = iterator.value;
-      int sourceTime = getModificationStamp(source);
-      if (sourceTime != sourceEntry.modificationTime) {
-        changedSources.add(source);
-      }
-      if (sourceEntry.exception != null) {
-        if (!exists(source)) {
-          missingSources.add(source);
-        }
-      }
-    }
-    int count = changedSources.length;
-    for (int i = 0; i < count; i++) {
-      _sourceChanged(changedSources[i]);
-    }
-    int removalCount = 0;
-    for (Source source in missingSources) {
-      if (getLibrariesContaining(source).isEmpty &&
-          getLibrariesDependingOn(source).isEmpty) {
-        _removeFromCache(source);
-        removalCount++;
-      }
-    }
-    int consistencyCheckEnd = JavaSystem.nanoTime();
-    if (changedSources.length > 0 || missingSources.length > 0) {
-      StringBuffer buffer = new StringBuffer();
-      buffer.write("Consistency check took ");
-      buffer.write((consistencyCheckEnd - consistencyCheckStart) / 1000000.0);
-      buffer.writeln(" ms and found");
-      buffer.write("  ");
-      buffer.write(changedSources.length);
-      buffer.writeln(" inconsistent entries");
-      buffer.write("  ");
-      buffer.write(missingSources.length);
-      buffer.write(" missing sources (");
-      buffer.write(removalCount);
-      buffer.writeln(" removed");
-      for (Source source in missingSources) {
-        buffer.write("    ");
-        buffer.writeln(source.fullName);
-      }
-      _logInformation(buffer.toString());
-    }
-    return changedSources.length > 0;
-  }
-
-  @deprecated
-  @override
-  void visitCacheItems(void callback(Source source, SourceEntry dartEntry,
-      DataDescriptor rowDesc, CacheState state)) {
-    bool hintsEnabled = _options.hint;
-    bool lintsEnabled = _options.lint;
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      SourceEntry sourceEntry = iterator.value;
-      for (DataDescriptor descriptor in sourceEntry.descriptors) {
-        if (descriptor == DartEntry.SOURCE_KIND) {
-          // The source kind is always valid, so the state isn't interesting.
-          continue;
-        } else if (descriptor == DartEntry.CONTAINING_LIBRARIES) {
-          // The list of containing libraries is always valid, so the state
-          // isn't interesting.
-          continue;
-        } else if (descriptor == DartEntry.PUBLIC_NAMESPACE) {
-          // The public namespace isn't computed by performAnalysisTask()
-          // and therefore isn't interesting.
-          continue;
-        } else if (descriptor == HtmlEntry.HINTS) {
-          // We are not currently recording any hints related to HTML.
-          continue;
-        }
-        callback(
-            source, sourceEntry, descriptor, sourceEntry.getState(descriptor));
-      }
-      if (sourceEntry is DartEntry) {
-        // get library-specific values
-        List<Source> librarySources = getLibrariesContaining(source);
-        for (Source librarySource in librarySources) {
-          for (DataDescriptor descriptor in sourceEntry.libraryDescriptors) {
-            if (descriptor == DartEntry.BUILT_ELEMENT ||
-                descriptor == DartEntry.BUILT_UNIT) {
-              // These values are not currently being computed, so their state
-              // is not interesting.
-              continue;
-            } else if (!sourceEntry.explicitlyAdded &&
-                !_generateImplicitErrors &&
-                (descriptor == DartEntry.VERIFICATION_ERRORS ||
-                    descriptor == DartEntry.HINTS ||
-                    descriptor == DartEntry.LINTS)) {
-              continue;
-            } else if (source.isInSystemLibrary &&
-                !_generateSdkErrors &&
-                (descriptor == DartEntry.VERIFICATION_ERRORS ||
-                    descriptor == DartEntry.HINTS ||
-                    descriptor == DartEntry.LINTS)) {
-              continue;
-            } else if (!hintsEnabled && descriptor == DartEntry.HINTS) {
-              continue;
-            } else if (!lintsEnabled && descriptor == DartEntry.LINTS) {
-              continue;
-            }
-            callback(librarySource, sourceEntry, descriptor,
-                sourceEntry.getStateInLibrary(descriptor, librarySource));
-          }
-        }
-      }
-    }
-  }
-
-  @override
-  void visitContentCache(ContentCacheVisitor visitor) {
-    _contentCache.accept(visitor);
-  }
-
-  /**
-   * Record that we have accessed the AST structure associated with the given
-   * [source]. At the moment, there is no differentiation between the parsed and
-   * resolved forms of the AST.
-   */
-  void _accessedAst(Source source) {
-    _cache.accessedAst(source);
-  }
-
-  /**
-   * Add all of the sources contained in the given source [container] to the
-   * given list of [sources].
-   */
-  void _addSourcesInContainer(List<Source> sources, SourceContainer container) {
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      if (container.contains(source)) {
-        sources.add(source);
-      }
-    }
-  }
-
-  /**
-   * Given the [unitSource] of a Dart file and the [librarySource] of the
-   * library that contains it, return a cache entry in which the state of the
-   * data represented by the given [descriptor] is either [CacheState.VALID] or
-   * [CacheState.ERROR]. This method assumes that the data can be produced by
-   * generating hints for the library if the data is not already cached. The
-   * [dartEntry] is the cache entry associated with the Dart file.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be parsed.
-   */
-  DartEntry _cacheDartHintData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information.
-      // Unless the modification date of the source continues to change,
-      // this loop will eventually terminate.
-      //
-      DartEntry libraryEntry = _getReadableDartEntry(librarySource);
-      libraryEntry = _cacheDartResolutionData(
-          librarySource, librarySource, libraryEntry, DartEntry.ELEMENT);
-      LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-      CompilationUnitElement definingUnit =
-          libraryElement.definingCompilationUnit;
-      List<CompilationUnitElement> parts = libraryElement.parts;
-      List<TimestampedData<CompilationUnit>> units =
-          new List<TimestampedData<CompilationUnit>>(parts.length + 1);
-      units[0] = _getResolvedUnit(definingUnit, librarySource);
-      if (units[0] == null) {
-        Source source = definingUnit.source;
-        units[0] = new TimestampedData<CompilationUnit>(
-            getModificationStamp(source),
-            resolveCompilationUnit(source, libraryElement));
-      }
-      for (int i = 0; i < parts.length; i++) {
-        units[i + 1] = _getResolvedUnit(parts[i], librarySource);
-        if (units[i + 1] == null) {
-          Source source = parts[i].source;
-          units[i + 1] = new TimestampedData<CompilationUnit>(
-              getModificationStamp(source),
-              resolveCompilationUnit(source, libraryElement));
-        }
-      }
-      dartEntry = new GenerateDartHintsTask(
-              this, units, getLibraryElement(librarySource))
-          .perform(_resultRecorder) as DartEntry;
-      state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return a
-   * cache entry in which the state of the data represented by the given
-   * descriptor is either [CacheState.VALID] or [CacheState.ERROR]. This method
-   * assumes that the data can be produced by generating lints for the library
-   * if the data is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  DartEntry _cacheDartLintData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information.
-      // Unless the modification date of the source continues to change,
-      // this loop will eventually terminate.
-      //
-      DartEntry libraryEntry = _getReadableDartEntry(librarySource);
-      libraryEntry = _cacheDartResolutionData(
-          librarySource, librarySource, libraryEntry, DartEntry.ELEMENT);
-      LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-      CompilationUnitElement definingUnit =
-          libraryElement.definingCompilationUnit;
-      List<CompilationUnitElement> parts = libraryElement.parts;
-      List<TimestampedData<CompilationUnit>> units =
-          new List<TimestampedData<CompilationUnit>>(parts.length + 1);
-      units[0] = _getResolvedUnit(definingUnit, librarySource);
-      if (units[0] == null) {
-        Source source = definingUnit.source;
-        units[0] = new TimestampedData<CompilationUnit>(
-            getModificationStamp(source),
-            resolveCompilationUnit(source, libraryElement));
-      }
-      for (int i = 0; i < parts.length; i++) {
-        units[i + 1] = _getResolvedUnit(parts[i], librarySource);
-        if (units[i + 1] == null) {
-          Source source = parts[i].source;
-          units[i + 1] = new TimestampedData<CompilationUnit>(
-              getModificationStamp(source),
-              resolveCompilationUnit(source, libraryElement));
-        }
-      }
-      //TODO(pquitslund): revisit if we need all units or whether one will do
-      dartEntry = new GenerateDartLintsTask(
-              this, units, getLibraryElement(librarySource))
-          .perform(_resultRecorder) as DartEntry;
-      state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for a Dart file, return a cache entry in which the state of
-   * the data represented by the given descriptor is either [CacheState.VALID]
-   * or [CacheState.ERROR]. This method assumes that the data can be produced by
-   * parsing the source if it is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  DartEntry _cacheDartParseData(
-      Source source, DartEntry dartEntry, DataDescriptor descriptor) {
-    if (identical(descriptor, DartEntry.PARSED_UNIT)) {
-      if (dartEntry.hasResolvableCompilationUnit) {
-        return dartEntry;
-      }
-    }
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = dartEntry.getState(descriptor);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      dartEntry = _cacheDartScanData(source, dartEntry, DartEntry.TOKEN_STREAM);
-      dartEntry = new ParseDartTask(
-              this,
-              source,
-              dartEntry.getValue(DartEntry.TOKEN_STREAM),
-              dartEntry.getValue(SourceEntry.LINE_INFO))
-          .perform(_resultRecorder) as DartEntry;
-      state = dartEntry.getState(descriptor);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return a
-   * cache entry in which the state of the data represented by the given
-   * descriptor is either [CacheState.VALID] or [CacheState.ERROR]. This method
-   * assumes that the data can be produced by resolving the source in the
-   * context of the library if it is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  DartEntry _cacheDartResolutionData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = (identical(descriptor, DartEntry.ELEMENT))
-        ? dartEntry.getState(descriptor)
-        : dartEntry.getStateInLibrary(descriptor, librarySource);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      // TODO(brianwilkerson) As an optimization, if we already have the
-      // element model for the library we can use ResolveDartUnitTask to produce
-      // the resolved AST structure much faster.
-      dartEntry = new ResolveDartLibraryTask(this, unitSource, librarySource)
-          .perform(_resultRecorder) as DartEntry;
-      state = (identical(descriptor, DartEntry.ELEMENT))
-          ? dartEntry.getState(descriptor)
-          : dartEntry.getStateInLibrary(descriptor, librarySource);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for a Dart file, return a cache entry in which the state of
-   * the data represented by the given descriptor is either [CacheState.VALID]
-   * or [CacheState.ERROR]. This method assumes that the data can be produced by
-   * scanning the source if it is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  DartEntry _cacheDartScanData(
-      Source source, DartEntry dartEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = dartEntry.getState(descriptor);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      try {
-        if (dartEntry.getState(SourceEntry.CONTENT) != CacheState.VALID) {
-          dartEntry = new GetContentTask(this, source).perform(_resultRecorder)
-              as DartEntry;
-        }
-        dartEntry = new ScanDartTask(
-                this, source, dartEntry.getValue(SourceEntry.CONTENT))
-            .perform(_resultRecorder) as DartEntry;
-      } on AnalysisException catch (exception) {
-        throw exception;
-      } catch (exception, stackTrace) {
-        throw new AnalysisException(
-            "Exception", new CaughtException(exception, stackTrace));
-      }
-      state = dartEntry.getState(descriptor);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return a
-   * cache entry in which the state of the data represented by the given
-   * descriptor is either [CacheState.VALID] or [CacheState.ERROR]. This method
-   * assumes that the data can be produced by verifying the source in the given
-   * library if the data is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  DartEntry _cacheDartVerificationData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      LibraryElement library = computeLibraryElement(librarySource);
-      CompilationUnit unit = resolveCompilationUnit(unitSource, library);
-      if (unit == null) {
-        throw new AnalysisException(
-            "Could not resolve compilation unit ${unitSource.fullName} in ${librarySource.fullName}");
-      }
-      dartEntry = new GenerateDartErrorsTask(this, unitSource, unit, library)
-          .perform(_resultRecorder) as DartEntry;
-      state = dartEntry.getStateInLibrary(descriptor, librarySource);
-    }
-    return dartEntry;
-  }
-
-  /**
-   * Given a source for an HTML file, return a cache entry in which all of the
-   * data represented by the state of the given descriptors is either
-   * [CacheState.VALID] or [CacheState.ERROR]. This method assumes that the data
-   * can be produced by parsing the source if it is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  HtmlEntry _cacheHtmlParseData(
-      Source source, HtmlEntry htmlEntry, DataDescriptor descriptor) {
-    if (identical(descriptor, HtmlEntry.PARSED_UNIT)) {
-      ht.HtmlUnit unit = htmlEntry.anyParsedUnit;
-      if (unit != null) {
-        return htmlEntry;
-      }
-    }
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = htmlEntry.getState(descriptor);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      try {
-        if (htmlEntry.getState(SourceEntry.CONTENT) != CacheState.VALID) {
-          htmlEntry = new GetContentTask(this, source).perform(_resultRecorder)
-              as HtmlEntry;
-        }
-        htmlEntry = new ParseHtmlTask(
-                this, source, htmlEntry.getValue(SourceEntry.CONTENT))
-            .perform(_resultRecorder) as HtmlEntry;
-      } on AnalysisException catch (exception) {
-        throw exception;
-      } catch (exception, stackTrace) {
-        throw new AnalysisException(
-            "Exception", new CaughtException(exception, stackTrace));
-      }
-      state = htmlEntry.getState(descriptor);
-    }
-    return htmlEntry;
-  }
-
-  /**
-   * Given a source for an HTML file, return a cache entry in which the state of
-   * the data represented by the given descriptor is either [CacheState.VALID]
-   * or [CacheState.ERROR]. This method assumes that the data can be produced by
-   * resolving the source if it is not already cached.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  HtmlEntry _cacheHtmlResolutionData(
-      Source source, HtmlEntry htmlEntry, DataDescriptor descriptor) {
-    //
-    // Check to see whether we already have the information being requested.
-    //
-    CacheState state = htmlEntry.getState(descriptor);
-    while (state != CacheState.ERROR && state != CacheState.VALID) {
-      //
-      // If not, compute the information. Unless the modification date of the
-      // source continues to change, this loop will eventually terminate.
-      //
-      htmlEntry = _cacheHtmlParseData(source, htmlEntry, HtmlEntry.PARSED_UNIT);
-      htmlEntry = new ResolveHtmlTask(this, source, htmlEntry.modificationTime,
-              htmlEntry.getValue(HtmlEntry.PARSED_UNIT))
-          .perform(_resultRecorder) as HtmlEntry;
-      state = htmlEntry.getState(descriptor);
-    }
-    return htmlEntry;
-  }
-
-  /**
-   * Remove the given [pendingFuture] from [_pendingFutureSources], since the
-   * client has indicated its computation is not needed anymore.
-   */
-  void _cancelFuture(PendingFuture pendingFuture) {
-    List<PendingFuture> pendingFutures =
-        _pendingFutureSources[pendingFuture.source];
-    if (pendingFutures != null) {
-      pendingFutures.remove(pendingFuture);
-      if (pendingFutures.isEmpty) {
-        _pendingFutureSources.remove(pendingFuture.source);
-      }
-    }
-  }
-
-  /**
-   * Compute the transitive closure of all libraries that depend on the given
-   * [library] by adding such libraries to the given collection of
-   * [librariesToInvalidate].
-   */
-  void _computeAllLibrariesDependingOn(
-      Source library, HashSet<Source> librariesToInvalidate) {
-    if (librariesToInvalidate.add(library)) {
-      for (Source dependentLibrary in getLibrariesDependingOn(library)) {
-        _computeAllLibrariesDependingOn(
-            dependentLibrary, librariesToInvalidate);
-      }
-    }
-  }
-
-  /**
-   * Return the priority that should be used when the source associated with
-   * the given [dartEntry] is added to the work manager.
-   */
-  SourcePriority _computePriority(DartEntry dartEntry) {
-    SourceKind kind = dartEntry.kind;
-    if (kind == SourceKind.LIBRARY) {
-      return SourcePriority.LIBRARY;
-    } else if (kind == SourceKind.PART) {
-      return SourcePriority.NORMAL_PART;
-    }
-    return SourcePriority.UNKNOWN;
-  }
-
-  /**
-   * Given the encoded form of a source ([encoding]), use the source factory to
-   * reconstitute the original source.
-   */
-  Source _computeSourceFromEncoding(String encoding) =>
-      _sourceFactory.fromEncoding(encoding);
-
-  /**
-   * Return `true` if the given list of [sources] contains the given
-   * [targetSource].
-   */
-  bool _contains(List<Source> sources, Source targetSource) {
-    for (Source source in sources) {
-      if (source == targetSource) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Return `true` if the given list of [sources] contains any of the given
-   * [targetSources].
-   */
-  bool _containsAny(List<Source> sources, List<Source> targetSources) {
-    for (Source targetSource in targetSources) {
-      if (_contains(sources, targetSource)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Set the contents of the given [source] to the given [contents] and mark the
-   * source as having changed. The additional [offset], [oldLength] and
-   * [newLength] information is used by the context to determine what reanalysis
-   * is necessary. The method [setChangedContents] triggers a source changed
-   * event where as this method does not.
-   */
-  bool _contentRangeChanged(Source source, String contents, int offset,
-      int oldLength, int newLength) {
-    bool changed = false;
-    String originalContents = _contentCache.setContents(source, contents);
-    if (contents != null) {
-      if (contents != originalContents) {
-        if (_options.incremental) {
-          _incrementalAnalysisCache = IncrementalAnalysisCache.update(
-              _incrementalAnalysisCache,
-              source,
-              originalContents,
-              contents,
-              offset,
-              oldLength,
-              newLength,
-              _getReadableSourceEntry(source));
-        }
-        _sourceChanged(source);
-        changed = true;
-        SourceEntry sourceEntry = _cache.get(source);
-        if (sourceEntry != null) {
-          sourceEntry.modificationTime =
-              _contentCache.getModificationStamp(source);
-          sourceEntry.setValue(SourceEntry.CONTENT, contents);
-        }
-      }
-    } else if (originalContents != null) {
-      _incrementalAnalysisCache =
-          IncrementalAnalysisCache.clear(_incrementalAnalysisCache, source);
-      _sourceChanged(source);
-      changed = true;
-    }
-    return changed;
-  }
-
-  /**
-   * Set the contents of the given [source] to the given [contents] and mark the
-   * source as having changed. This has the effect of overriding the default
-   * contents of the source. If the contents are `null` the override is removed
-   * so that the default contents will be returned. If [notify] is true, a
-   * source changed event is triggered.
-   */
-  void _contentsChanged(Source source, String contents, bool notify) {
-    String originalContents = _contentCache.setContents(source, contents);
-    handleContentsChanged(source, originalContents, contents, notify);
-  }
-
-  /**
-   * Create a [GenerateDartErrorsTask] for the given [unitSource], marking the
-   * verification errors as being in-process. The compilation unit and the
-   * library can be the same if the compilation unit is the defining compilation
-   * unit of the library.
-   */
-  AnalysisContextImpl_TaskData _createGenerateDartErrorsTask(Source unitSource,
-      DartEntry unitEntry, Source librarySource, DartEntry libraryEntry) {
-    if (unitEntry.getStateInLibrary(DartEntry.RESOLVED_UNIT, librarySource) !=
-            CacheState.VALID ||
-        libraryEntry.getState(DartEntry.ELEMENT) != CacheState.VALID) {
-      return _createResolveDartLibraryTask(librarySource, libraryEntry);
-    }
-    CompilationUnit unit =
-        unitEntry.getValueInLibrary(DartEntry.RESOLVED_UNIT, librarySource);
-    if (unit == null) {
-      CaughtException exception = new CaughtException(
-          new AnalysisException(
-              "Entry has VALID state for RESOLVED_UNIT but null value for ${unitSource.fullName} in ${librarySource.fullName}"),
-          null);
-      AnalysisEngine.instance.logger
-          .logInformation(exception.toString(), exception);
-      unitEntry.recordResolutionError(exception);
-      return new AnalysisContextImpl_TaskData(null, false);
-    }
-    LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-    return new AnalysisContextImpl_TaskData(
-        new GenerateDartErrorsTask(this, unitSource, unit, libraryElement),
-        false);
-  }
-
-  /**
-   * Create a [GenerateDartHintsTask] for the given [source], marking the hints
-   * as being in-process.
-   */
-  AnalysisContextImpl_TaskData _createGenerateDartHintsTask(Source source,
-      DartEntry dartEntry, Source librarySource, DartEntry libraryEntry) {
-    if (libraryEntry.getState(DartEntry.ELEMENT) != CacheState.VALID) {
-      return _createResolveDartLibraryTask(librarySource, libraryEntry);
-    }
-    LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-    CompilationUnitElement definingUnit =
-        libraryElement.definingCompilationUnit;
-    List<CompilationUnitElement> parts = libraryElement.parts;
-    List<TimestampedData<CompilationUnit>> units =
-        new List<TimestampedData<CompilationUnit>>(parts.length + 1);
-    units[0] = _getResolvedUnit(definingUnit, librarySource);
-    if (units[0] == null) {
-      // TODO(brianwilkerson) We should return a ResolveDartUnitTask
-      // (unless there are multiple ASTs that need to be resolved).
-      return _createResolveDartLibraryTask(librarySource, libraryEntry);
-    }
-    for (int i = 0; i < parts.length; i++) {
-      units[i + 1] = _getResolvedUnit(parts[i], librarySource);
-      if (units[i + 1] == null) {
-        // TODO(brianwilkerson) We should return a ResolveDartUnitTask
-        // (unless there are multiple ASTs that need to be resolved).
-        return _createResolveDartLibraryTask(librarySource, libraryEntry);
-      }
-    }
-    return new AnalysisContextImpl_TaskData(
-        new GenerateDartHintsTask(this, units, libraryElement), false);
-  }
-
-  /**
-   * Create a [GenerateDartLintsTask] for the given [source], marking the lints
-   * as being in-process.
-   */
-  AnalysisContextImpl_TaskData _createGenerateDartLintsTask(Source source,
-      DartEntry dartEntry, Source librarySource, DartEntry libraryEntry) {
-    if (libraryEntry.getState(DartEntry.ELEMENT) != CacheState.VALID) {
-      return _createResolveDartLibraryTask(librarySource, libraryEntry);
-    }
-    LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-    CompilationUnitElement definingUnit =
-        libraryElement.definingCompilationUnit;
-    List<CompilationUnitElement> parts = libraryElement.parts;
-    List<TimestampedData<CompilationUnit>> units =
-        new List<TimestampedData<CompilationUnit>>(parts.length + 1);
-    units[0] = _getResolvedUnit(definingUnit, librarySource);
-    if (units[0] == null) {
-      // TODO(brianwilkerson) We should return a ResolveDartUnitTask
-      // (unless there are multiple ASTs that need to be resolved).
-      return _createResolveDartLibraryTask(librarySource, libraryEntry);
-    }
-    for (int i = 0; i < parts.length; i++) {
-      units[i + 1] = _getResolvedUnit(parts[i], librarySource);
-      if (units[i + 1] == null) {
-        // TODO(brianwilkerson) We should return a ResolveDartUnitTask
-        // (unless there are multiple ASTs that need to be resolved).
-        return _createResolveDartLibraryTask(librarySource, libraryEntry);
-      }
-    }
-    //TODO(pquitslund): revisit if we need all units or whether one will do
-    return new AnalysisContextImpl_TaskData(
-        new GenerateDartLintsTask(this, units, libraryElement), false);
-  }
-
-  /**
-   * Create a [GetContentTask] for the given [source], marking the content as
-   * being in-process.
-   */
-  AnalysisContextImpl_TaskData _createGetContentTask(
-      Source source, SourceEntry sourceEntry) {
-    return new AnalysisContextImpl_TaskData(
-        new GetContentTask(this, source), false);
-  }
-
-  /**
-   * Create a [ParseDartTask] for the given [source].
-   */
-  AnalysisContextImpl_TaskData _createParseDartTask(
-      Source source, DartEntry dartEntry) {
-    if (dartEntry.getState(DartEntry.TOKEN_STREAM) != CacheState.VALID ||
-        dartEntry.getState(SourceEntry.LINE_INFO) != CacheState.VALID) {
-      return _createScanDartTask(source, dartEntry);
-    }
-    Token tokenStream = dartEntry.getValue(DartEntry.TOKEN_STREAM);
-    dartEntry.setState(DartEntry.TOKEN_STREAM, CacheState.FLUSHED);
-    return new AnalysisContextImpl_TaskData(
-        new ParseDartTask(this, source, tokenStream,
-            dartEntry.getValue(SourceEntry.LINE_INFO)),
-        false);
-  }
-
-  /**
-   * Create a [ParseHtmlTask] for the given [source].
-   */
-  AnalysisContextImpl_TaskData _createParseHtmlTask(
-      Source source, HtmlEntry htmlEntry) {
-    if (htmlEntry.getState(SourceEntry.CONTENT) != CacheState.VALID) {
-      return _createGetContentTask(source, htmlEntry);
-    }
-    String content = htmlEntry.getValue(SourceEntry.CONTENT);
-    htmlEntry.setState(SourceEntry.CONTENT, CacheState.FLUSHED);
-    return new AnalysisContextImpl_TaskData(
-        new ParseHtmlTask(this, source, content), false);
-  }
-
-  /**
-   * Create a [ResolveDartLibraryTask] for the given [source], marking ? as
-   * being in-process.
-   */
-  AnalysisContextImpl_TaskData _createResolveDartLibraryTask(
-      Source source, DartEntry dartEntry) {
-    try {
-      AnalysisContextImpl_CycleBuilder builder =
-          new AnalysisContextImpl_CycleBuilder(this);
-      PerformanceStatistics.cycles.makeCurrentWhile(() {
-        builder.computeCycleContaining(source);
-      });
-      AnalysisContextImpl_TaskData taskData = builder.taskData;
-      if (taskData != null) {
-        return taskData;
-      }
-      return new AnalysisContextImpl_TaskData(
-          new ResolveDartLibraryCycleTask(
-              this, source, source, builder.librariesInCycle),
-          false);
-    } on AnalysisException catch (exception, stackTrace) {
-      dartEntry
-          .recordResolutionError(new CaughtException(exception, stackTrace));
-      AnalysisEngine.instance.logger.logError(
-          "Internal error trying to create a ResolveDartLibraryTask",
-          new CaughtException(exception, stackTrace));
-    }
-    return new AnalysisContextImpl_TaskData(null, false);
-  }
-
-  /**
-   * Create a [ResolveHtmlTask] for the given [source], marking the resolved
-   * unit as being in-process.
-   */
-  AnalysisContextImpl_TaskData _createResolveHtmlTask(
-      Source source, HtmlEntry htmlEntry) {
-    if (htmlEntry.getState(HtmlEntry.PARSED_UNIT) != CacheState.VALID) {
-      return _createParseHtmlTask(source, htmlEntry);
-    }
-    return new AnalysisContextImpl_TaskData(
-        new ResolveHtmlTask(this, source, htmlEntry.modificationTime,
-            htmlEntry.getValue(HtmlEntry.PARSED_UNIT)),
-        false);
-  }
-
-  /**
-   * Create a [ScanDartTask] for the given [source], marking the scan errors as
-   * being in-process.
-   */
-  AnalysisContextImpl_TaskData _createScanDartTask(
-      Source source, DartEntry dartEntry) {
-    if (dartEntry.getState(SourceEntry.CONTENT) != CacheState.VALID) {
-      return _createGetContentTask(source, dartEntry);
-    }
-    String content = dartEntry.getValue(SourceEntry.CONTENT);
-    dartEntry.setState(SourceEntry.CONTENT, CacheState.FLUSHED);
-    return new AnalysisContextImpl_TaskData(
-        new ScanDartTask(this, source, content), false);
-  }
-
-  /**
-   * Create a source entry for the given [source]. Return the source entry that
-   * was created, or `null` if the source should not be tracked by this context.
-   */
-  SourceEntry _createSourceEntry(Source source, bool explicitlyAdded) {
-    String name = source.shortName;
-    if (AnalysisEngine.isHtmlFileName(name)) {
-      HtmlEntry htmlEntry = new HtmlEntry();
-      htmlEntry.modificationTime = getModificationStamp(source);
-      htmlEntry.explicitlyAdded = explicitlyAdded;
-      _cache.put(source, htmlEntry);
-      if (!explicitlyAdded) {
-        _implicitAnalysisEventsController
-            .add(new ImplicitAnalysisEvent(source, true));
-      }
-      return htmlEntry;
-    } else {
-      DartEntry dartEntry = new DartEntry();
-      dartEntry.modificationTime = getModificationStamp(source);
-      dartEntry.explicitlyAdded = explicitlyAdded;
-      _cache.put(source, dartEntry);
-      if (!explicitlyAdded) {
-        _implicitAnalysisEventsController
-            .add(new ImplicitAnalysisEvent(source, true));
-      }
-      return dartEntry;
-    }
-  }
-
-  /**
-   * Return a list containing all of the change notices that are waiting to be
-   * returned. If there are no notices, then return either `null` or an empty
-   * list, depending on the value of [nullIfEmpty].
-   */
-  List<ChangeNotice> _getChangeNotices(bool nullIfEmpty) {
-    if (_pendingNotices.isEmpty) {
-      if (nullIfEmpty) {
-        return null;
-      }
-      return ChangeNoticeImpl.EMPTY_LIST;
-    }
-    List<ChangeNotice> notices = new List.from(_pendingNotices.values);
-    _pendingNotices.clear();
-    return notices;
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return the
-   * data represented by the given descriptor that is associated with that
-   * source. This method assumes that the data can be produced by generating
-   * hints for the library if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartHintData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry =
-        _cacheDartHintData(unitSource, librarySource, dartEntry, descriptor);
-    if (identical(descriptor, DartEntry.ELEMENT)) {
-      return dartEntry.getValue(descriptor);
-    }
-    return dartEntry.getValueInLibrary(descriptor, librarySource);
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return the
-   * data represented by the given descriptor that is associated with that
-   * source. This method assumes that the data can be produced by generating
-   * lints for the library if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartLintData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry =
-        _cacheDartLintData(unitSource, librarySource, dartEntry, descriptor);
-    if (identical(descriptor, DartEntry.ELEMENT)) {
-      return dartEntry.getValue(descriptor);
-    }
-    return dartEntry.getValueInLibrary(descriptor, librarySource);
-  }
-
-  /**
-   * Given a source for a Dart file, return the data represented by the given
-   * descriptor that is associated with that source. This method assumes that
-   * the data can be produced by parsing the source if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be parsed.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartParseData(
-      Source source, DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry = _cacheDartParseData(source, dartEntry, descriptor);
-    if (identical(descriptor, DartEntry.PARSED_UNIT)) {
-      _accessedAst(source);
-      return dartEntry.anyParsedCompilationUnit;
-    }
-    return dartEntry.getValue(descriptor);
-  }
-
-  /**
-   * Given a source for a Dart file, return the data represented by the given
-   * descriptor that is associated with that source, or the given default value
-   * if the source is not a Dart file. This method assumes that the data can be
-   * produced by parsing the source if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be parsed.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartParseData2(
-      Source source, DataDescriptor descriptor, Object defaultValue) {
-    DartEntry dartEntry = _getReadableDartEntry(source);
-    if (dartEntry == null) {
-      return defaultValue;
-    }
-    try {
-      return _getDartParseData(source, dartEntry, descriptor);
-    } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logInformation(
-          "Could not compute $descriptor",
-          new CaughtException(exception, stackTrace));
-      return defaultValue;
-    }
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return the
-   * data represented by the given descriptor that is associated with that
-   * source. This method assumes that the data can be produced by resolving the
-   * source in the context of the library if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartResolutionData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry = _cacheDartResolutionData(
-        unitSource, librarySource, dartEntry, descriptor);
-    if (identical(descriptor, DartEntry.ELEMENT)) {
-      return dartEntry.getValue(descriptor);
-    } else if (identical(descriptor, DartEntry.RESOLVED_UNIT)) {
-      _accessedAst(unitSource);
-    }
-    return dartEntry.getValueInLibrary(descriptor, librarySource);
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return the
-   * data represented by the given descriptor that is associated with that
-   * source, or the given default value if the source is not a Dart file. This
-   * method assumes that the data can be produced by resolving the source in the
-   * context of the library if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartResolutionData2(Source unitSource, Source librarySource,
-      DataDescriptor descriptor, Object defaultValue) {
-    DartEntry dartEntry = _getReadableDartEntry(unitSource);
-    if (dartEntry == null) {
-      return defaultValue;
-    }
-    try {
-      return _getDartResolutionData(
-          unitSource, librarySource, dartEntry, descriptor);
-    } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logInformation(
-          "Could not compute $descriptor",
-          new CaughtException(exception, stackTrace));
-      return defaultValue;
-    }
-  }
-
-  /**
-   * Given a source for a Dart file, return the data represented by the given
-   * descriptor that is associated with that source. This method assumes that
-   * the data can be produced by scanning the source if it is not already
-   * cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be scanned.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartScanData(
-      Source source, DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry = _cacheDartScanData(source, dartEntry, descriptor);
-    return dartEntry.getValue(descriptor);
-  }
-
-  /**
-   * Given a source for a Dart file, return the data represented by the given
-   * descriptor that is associated with that source, or the given default value
-   * if the source is not a Dart file. This method assumes that the data can be
-   * produced by scanning the source if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be scanned.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartScanData2(
-      Source source, DataDescriptor descriptor, Object defaultValue) {
-    DartEntry dartEntry = _getReadableDartEntry(source);
-    if (dartEntry == null) {
-      return defaultValue;
-    }
-    try {
-      return _getDartScanData(source, dartEntry, descriptor);
-    } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logInformation(
-          "Could not compute $descriptor",
-          new CaughtException(exception, stackTrace));
-      return defaultValue;
-    }
-  }
-
-  /**
-   * Given a source for a Dart file and the library that contains it, return the
-   * data represented by the given descriptor that is associated with that
-   * source. This method assumes that the data can be produced by verifying the
-   * source within the given library if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getDartVerificationData(Source unitSource, Source librarySource,
-      DartEntry dartEntry, DataDescriptor descriptor) {
-    dartEntry = _cacheDartVerificationData(
-        unitSource, librarySource, dartEntry, descriptor);
-    return dartEntry.getValueInLibrary(descriptor, librarySource);
-  }
-
-  /**
-   * Given a source for an HTML file, return the data represented by the given
-   * descriptor that is associated with that source, or the given default value
-   * if the source is not an HTML file. This method assumes that the data can be
-   * produced by parsing the source if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be parsed.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getHtmlParseData(
-      Source source, DataDescriptor descriptor, Object defaultValue) {
-    HtmlEntry htmlEntry = _getReadableHtmlEntry(source);
-    if (htmlEntry == null) {
-      return defaultValue;
-    }
-    htmlEntry = _cacheHtmlParseData(source, htmlEntry, descriptor);
-    if (identical(descriptor, HtmlEntry.PARSED_UNIT)) {
-      _accessedAst(source);
-      return htmlEntry.anyParsedUnit;
-    }
-    return htmlEntry.getValue(descriptor);
-  }
-
-  /**
-   * Given a source for an HTML file, return the data represented by the given
-   * descriptor that is associated with that source, or the given default value
-   * if the source is not an HTML file. This method assumes that the data can be
-   * produced by resolving the source if it is not already cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getHtmlResolutionData(
-      Source source, DataDescriptor descriptor, Object defaultValue) {
-    HtmlEntry htmlEntry = _getReadableHtmlEntry(source);
-    if (htmlEntry == null) {
-      return defaultValue;
-    }
-    try {
-      return _getHtmlResolutionData2(source, htmlEntry, descriptor);
-    } on ObsoleteSourceAnalysisException catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logInformation(
-          "Could not compute $descriptor",
-          new CaughtException(exception, stackTrace));
-      return defaultValue;
-    }
-  }
-
-  /**
-   * Given a source for an HTML file, return the data represented by the given
-   * descriptor that is associated with that source. This method assumes that
-   * the data can be produced by resolving the source if it is not already
-   * cached.
-   *
-   * Throws an [AnalysisException] if data could not be returned because the
-   * source could not be resolved.
-   *
-   * <b>Note:</b> This method cannot be used in an async environment.
-   */
-  Object _getHtmlResolutionData2(
-      Source source, HtmlEntry htmlEntry, DataDescriptor descriptor) {
-    htmlEntry = _cacheHtmlResolutionData(source, htmlEntry, descriptor);
-    if (identical(descriptor, HtmlEntry.RESOLVED_UNIT)) {
-      _accessedAst(source);
-    }
-    return htmlEntry.getValue(descriptor);
-  }
-
-  /**
-   * Look at the given [source] to see whether a task needs to be performed
-   * related to it. Return the task that should be performed, or `null` if there
-   * is no more work to be done for the source.
-   */
-  AnalysisContextImpl_TaskData _getNextAnalysisTaskForSource(
-      Source source,
-      SourceEntry sourceEntry,
-      bool isPriority,
-      bool hintsEnabled,
-      bool lintsEnabled) {
-    // Refuse to generate tasks for html based files that are above 1500 KB
-    if (_isTooBigHtmlSourceEntry(source, sourceEntry)) {
-      // TODO (jwren) we still need to report an error of some kind back to the
-      // client.
-      return new AnalysisContextImpl_TaskData(null, false);
-    }
-    if (sourceEntry == null) {
-      return new AnalysisContextImpl_TaskData(null, false);
-    }
-    CacheState contentState = sourceEntry.getState(SourceEntry.CONTENT);
-    if (contentState == CacheState.INVALID) {
-      return _createGetContentTask(source, sourceEntry);
-    } else if (contentState == CacheState.IN_PROCESS) {
-      // We are already in the process of getting the content.
-      // There's nothing else we can do with this source until that's complete.
-      return new AnalysisContextImpl_TaskData(null, true);
-    } else if (contentState == CacheState.ERROR) {
-      // We have done all of the analysis we can for this source because we
-      // cannot get its content.
-      return new AnalysisContextImpl_TaskData(null, false);
-    }
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      CacheState scanErrorsState = dartEntry.getState(DartEntry.SCAN_ERRORS);
-      if (scanErrorsState == CacheState.INVALID ||
-          (isPriority && scanErrorsState == CacheState.FLUSHED)) {
-        return _createScanDartTask(source, dartEntry);
-      }
-      CacheState parseErrorsState = dartEntry.getState(DartEntry.PARSE_ERRORS);
-      if (parseErrorsState == CacheState.INVALID ||
-          (isPriority && parseErrorsState == CacheState.FLUSHED)) {
-        return _createParseDartTask(source, dartEntry);
-      }
-      if (isPriority && parseErrorsState != CacheState.ERROR) {
-        if (!dartEntry.hasResolvableCompilationUnit) {
-          return _createParseDartTask(source, dartEntry);
-        }
-      }
-      SourceKind kind = dartEntry.getValue(DartEntry.SOURCE_KIND);
-      if (kind == SourceKind.UNKNOWN) {
-        return _createParseDartTask(source, dartEntry);
-      } else if (kind == SourceKind.LIBRARY) {
-        CacheState elementState = dartEntry.getState(DartEntry.ELEMENT);
-        if (elementState == CacheState.INVALID) {
-          return _createResolveDartLibraryTask(source, dartEntry);
-        }
-      }
-      List<Source> librariesContaining = dartEntry.containingLibraries;
-      for (Source librarySource in librariesContaining) {
-        SourceEntry librarySourceEntry = _cache.get(librarySource);
-        if (librarySourceEntry is DartEntry) {
-          DartEntry libraryEntry = librarySourceEntry;
-          CacheState elementState = libraryEntry.getState(DartEntry.ELEMENT);
-          if (elementState == CacheState.INVALID ||
-              (isPriority && elementState == CacheState.FLUSHED)) {
-//            return createResolveDartLibraryTask(librarySource, (DartEntry) libraryEntry);
-            return new AnalysisContextImpl_TaskData(
-                new ResolveDartLibraryTask(this, source, librarySource), false);
-          }
-          CacheState resolvedUnitState = dartEntry.getStateInLibrary(
-              DartEntry.RESOLVED_UNIT, librarySource);
-          if (resolvedUnitState == CacheState.INVALID ||
-              (isPriority && resolvedUnitState == CacheState.FLUSHED)) {
-            //
-            // The commented out lines below are an optimization that doesn't
-            // quite work yet. The problem is that if the source was not
-            // resolved because it wasn't part of any library, then there won't
-            // be any elements in the element model that we can use to resolve
-            // it.
-            //
-//            LibraryElement libraryElement = libraryEntry.getValue(DartEntry.ELEMENT);
-//            if (libraryElement != null) {
-//              return new ResolveDartUnitTask(this, source, libraryElement);
-//            }
-            // Possibly replace with:
-//             return createResolveDartLibraryTask(librarySource, (DartEntry) libraryEntry);
-            return new AnalysisContextImpl_TaskData(
-                new ResolveDartLibraryTask(this, source, librarySource), false);
-          }
-          if (shouldErrorsBeAnalyzed(source, dartEntry)) {
-            CacheState verificationErrorsState = dartEntry.getStateInLibrary(
-                DartEntry.VERIFICATION_ERRORS, librarySource);
-            if (verificationErrorsState == CacheState.INVALID ||
-                (isPriority && verificationErrorsState == CacheState.FLUSHED)) {
-              return _createGenerateDartErrorsTask(
-                  source, dartEntry, librarySource, libraryEntry);
-            }
-            if (hintsEnabled) {
-              CacheState hintsState =
-                  dartEntry.getStateInLibrary(DartEntry.HINTS, librarySource);
-              if (hintsState == CacheState.INVALID ||
-                  (isPriority && hintsState == CacheState.FLUSHED)) {
-                return _createGenerateDartHintsTask(
-                    source, dartEntry, librarySource, libraryEntry);
-              }
-            }
-            if (lintsEnabled) {
-              CacheState lintsState =
-                  dartEntry.getStateInLibrary(DartEntry.LINTS, librarySource);
-              if (lintsState == CacheState.INVALID ||
-                  (isPriority && lintsState == CacheState.FLUSHED)) {
-                return _createGenerateDartLintsTask(
-                    source, dartEntry, librarySource, libraryEntry);
-              }
-            }
-          }
-        }
-      }
-    } else if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      CacheState parseErrorsState = htmlEntry.getState(HtmlEntry.PARSE_ERRORS);
-      if (parseErrorsState == CacheState.INVALID ||
-          (isPriority && parseErrorsState == CacheState.FLUSHED)) {
-        return _createParseHtmlTask(source, htmlEntry);
-      }
-      if (isPriority && parseErrorsState != CacheState.ERROR) {
-        ht.HtmlUnit parsedUnit = htmlEntry.anyParsedUnit;
-        if (parsedUnit == null) {
-          return _createParseHtmlTask(source, htmlEntry);
-        }
-      }
-      CacheState resolvedUnitState =
-          htmlEntry.getState(HtmlEntry.RESOLVED_UNIT);
-      if (resolvedUnitState == CacheState.INVALID ||
-          (isPriority && resolvedUnitState == CacheState.FLUSHED)) {
-        return _createResolveHtmlTask(source, htmlEntry);
-      }
-    }
-    return new AnalysisContextImpl_TaskData(null, false);
-  }
-
-  /**
-   * Return the cache entry associated with the given [source], or `null` if the
-   * source is not a Dart file.
-   *
-   * @param source the source for which a cache entry is being sought
-   * @return the source cache entry associated with the given source
-   */
-  DartEntry _getReadableDartEntry(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry == null) {
-      sourceEntry = _createSourceEntry(source, false);
-    }
-    if (sourceEntry is DartEntry) {
-      return sourceEntry;
-    }
-    return null;
-  }
-
-  /**
-   * Return the cache entry associated with the given [source], or `null` if the
-   * source is not an HTML file.
-   */
-  HtmlEntry _getReadableHtmlEntry(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry == null) {
-      sourceEntry = _createSourceEntry(source, false);
-    }
-    if (sourceEntry is HtmlEntry) {
-      return sourceEntry;
-    }
-    return null;
-  }
-
-  /**
-   * Return the cache entry associated with the given [source], creating it if
-   * necessary.
-   */
-  SourceEntry _getReadableSourceEntry(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry == null) {
-      sourceEntry = _createSourceEntry(source, false);
-    }
-    return sourceEntry;
-  }
-
-  /**
-   * Return a resolved compilation unit corresponding to the given [element] in
-   * the library defined by the given [librarySource], or `null` if the
-   * information is not cached.
-   */
-  TimestampedData<CompilationUnit> _getResolvedUnit(
-      CompilationUnitElement element, Source librarySource) {
-    SourceEntry sourceEntry = _cache.get(element.source);
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      if (dartEntry.getStateInLibrary(DartEntry.RESOLVED_UNIT, librarySource) ==
-          CacheState.VALID) {
-        return new TimestampedData<CompilationUnit>(
-            dartEntry.modificationTime,
-            dartEntry.getValueInLibrary(
-                DartEntry.RESOLVED_UNIT, librarySource));
-      }
-    }
-    return null;
-  }
-
-  /**
-   * Return a list containing all of the sources known to this context that have
-   * the given [kind].
-   */
-  List<Source> _getSources(SourceKind kind) {
-    List<Source> sources = new List<Source>();
-    MapIterator<Source, SourceEntry> iterator = _cache.iterator();
-    while (iterator.moveNext()) {
-      if (iterator.value.kind == kind) {
-        sources.add(iterator.key);
-      }
-    }
-    return sources;
-  }
-
-  /**
-   * Look at the given [source] to see whether a task needs to be performed
-   * related to it. If so, add the source to the set of sources that need to be
-   * processed. This method duplicates, and must therefore be kept in sync with,
-   * [_getNextAnalysisTaskForSource]. This method is intended to be used for
-   * testing purposes only.
-   */
-  void _getSourcesNeedingProcessing(
-      Source source,
-      SourceEntry sourceEntry,
-      bool isPriority,
-      bool hintsEnabled,
-      bool lintsEnabled,
-      HashSet<Source> sources) {
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      CacheState scanErrorsState = dartEntry.getState(DartEntry.SCAN_ERRORS);
-      if (scanErrorsState == CacheState.INVALID ||
-          (isPriority && scanErrorsState == CacheState.FLUSHED)) {
-        sources.add(source);
-        return;
-      }
-      CacheState parseErrorsState = dartEntry.getState(DartEntry.PARSE_ERRORS);
-      if (parseErrorsState == CacheState.INVALID ||
-          (isPriority && parseErrorsState == CacheState.FLUSHED)) {
-        sources.add(source);
-        return;
-      }
-      if (isPriority) {
-        if (!dartEntry.hasResolvableCompilationUnit) {
-          sources.add(source);
-          return;
-        }
-      }
-      for (Source librarySource in getLibrariesContaining(source)) {
-        SourceEntry libraryEntry = _cache.get(librarySource);
-        if (libraryEntry is DartEntry) {
-          CacheState elementState = libraryEntry.getState(DartEntry.ELEMENT);
-          if (elementState == CacheState.INVALID ||
-              (isPriority && elementState == CacheState.FLUSHED)) {
-            sources.add(source);
-            return;
-          }
-          CacheState resolvedUnitState = dartEntry.getStateInLibrary(
-              DartEntry.RESOLVED_UNIT, librarySource);
-          if (resolvedUnitState == CacheState.INVALID ||
-              (isPriority && resolvedUnitState == CacheState.FLUSHED)) {
-            LibraryElement libraryElement =
-                libraryEntry.getValue(DartEntry.ELEMENT);
-            if (libraryElement != null) {
-              sources.add(source);
-              return;
-            }
-          }
-          if (shouldErrorsBeAnalyzed(source, dartEntry)) {
-            CacheState verificationErrorsState = dartEntry.getStateInLibrary(
-                DartEntry.VERIFICATION_ERRORS, librarySource);
-            if (verificationErrorsState == CacheState.INVALID ||
-                (isPriority && verificationErrorsState == CacheState.FLUSHED)) {
-              LibraryElement libraryElement =
-                  libraryEntry.getValue(DartEntry.ELEMENT);
-              if (libraryElement != null) {
-                sources.add(source);
-                return;
-              }
-            }
-            if (hintsEnabled) {
-              CacheState hintsState =
-                  dartEntry.getStateInLibrary(DartEntry.HINTS, librarySource);
-              if (hintsState == CacheState.INVALID ||
-                  (isPriority && hintsState == CacheState.FLUSHED)) {
-                LibraryElement libraryElement =
-                    libraryEntry.getValue(DartEntry.ELEMENT);
-                if (libraryElement != null) {
-                  sources.add(source);
-                  return;
-                }
-              }
-            }
-            if (lintsEnabled) {
-              CacheState lintsState =
-                  dartEntry.getStateInLibrary(DartEntry.LINTS, librarySource);
-              if (lintsState == CacheState.INVALID ||
-                  (isPriority && lintsState == CacheState.FLUSHED)) {
-                LibraryElement libraryElement =
-                    libraryEntry.getValue(DartEntry.ELEMENT);
-                if (libraryElement != null) {
-                  sources.add(source);
-                  return;
-                }
-              }
-            }
-          }
-        }
-      }
-    } else if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      CacheState parsedUnitState = htmlEntry.getState(HtmlEntry.PARSED_UNIT);
-      if (parsedUnitState == CacheState.INVALID ||
-          (isPriority && parsedUnitState == CacheState.FLUSHED)) {
-        sources.add(source);
-        return;
-      }
-      CacheState resolvedUnitState =
-          htmlEntry.getState(HtmlEntry.RESOLVED_UNIT);
-      if (resolvedUnitState == CacheState.INVALID ||
-          (isPriority && resolvedUnitState == CacheState.FLUSHED)) {
-        sources.add(source);
-        return;
-      }
-    }
-  }
-
-  /**
-   * Invalidate all of the resolution results computed by this context. The flag
-   * [invalidateUris] should be `true` if the cached results of converting URIs
-   * to source files should also be invalidated.
-   */
-  void _invalidateAllLocalResolutionInformation(bool invalidateUris) {
-    HashMap<Source, List<Source>> oldPartMap =
-        new HashMap<Source, List<Source>>();
-    MapIterator<Source, SourceEntry> iterator = _privatePartition.iterator();
-    while (iterator.moveNext()) {
-      Source source = iterator.key;
-      SourceEntry sourceEntry = iterator.value;
-      if (sourceEntry is HtmlEntry) {
-        HtmlEntry htmlEntry = sourceEntry;
-        htmlEntry.invalidateAllResolutionInformation(invalidateUris);
-        iterator.value = htmlEntry;
-        _workManager.add(source, SourcePriority.HTML);
-      } else if (sourceEntry is DartEntry) {
-        DartEntry dartEntry = sourceEntry;
-        oldPartMap[source] = dartEntry.getValue(DartEntry.INCLUDED_PARTS);
-        dartEntry.invalidateAllResolutionInformation(invalidateUris);
-        iterator.value = dartEntry;
-        _workManager.add(source, _computePriority(dartEntry));
-      }
-    }
-    _removeFromPartsUsingMap(oldPartMap);
-  }
-
-  /**
-   * In response to a change to at least one of the compilation units in the
-   * library defined by the given [librarySource], invalidate any results that
-   * are dependent on the result of resolving that library.
-   *
-   * <b>Note:</b> Any cache entries that were accessed before this method was
-   * invoked must be re-accessed after this method returns.
-   */
-  void _invalidateLibraryResolution(Source librarySource) {
-    // TODO(brianwilkerson) This could be optimized. There's no need to flush
-    // all of these entries if the public namespace hasn't changed, which will
-    // be a fairly common case. The question is whether we can afford the time
-    // to compute the namespace to look for differences.
-    DartEntry libraryEntry = _getReadableDartEntry(librarySource);
-    if (libraryEntry != null) {
-      List<Source> includedParts =
-          libraryEntry.getValue(DartEntry.INCLUDED_PARTS);
-      libraryEntry.invalidateAllResolutionInformation(false);
-      _workManager.add(librarySource, SourcePriority.LIBRARY);
-      for (Source partSource in includedParts) {
-        SourceEntry partEntry = _cache.get(partSource);
-        if (partEntry is DartEntry) {
-          partEntry.invalidateAllResolutionInformation(false);
-        }
-      }
-    }
-  }
-
-  /**
-   * Return `true` if the given [library] is, or depends on, 'dart:html'. The
-   * [visitedLibraries] is a collection of the libraries that have been visited,
-   * used to prevent infinite recursion.
-   */
-  bool _isClient(LibraryElement library, Source htmlSource,
-      HashSet<LibraryElement> visitedLibraries) {
-    if (visitedLibraries.contains(library)) {
-      return false;
-    }
-    if (library.source == htmlSource) {
-      return true;
-    }
-    visitedLibraries.add(library);
-    for (LibraryElement imported in library.importedLibraries) {
-      if (_isClient(imported, htmlSource, visitedLibraries)) {
-        return true;
-      }
-    }
-    for (LibraryElement exported in library.exportedLibraries) {
-      if (_isClient(exported, htmlSource, visitedLibraries)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  bool _isTooBigHtmlSourceEntry(Source source, SourceEntry sourceEntry) =>
-      false;
-
-//  /**
-//   * Notify all of the analysis listeners that the given source is no longer included in the set of
-//   * sources that are being analyzed.
-//   *
-//   * @param source the source that is no longer being analyzed
-//   */
-//  void _notifyExcludedSource(Source source) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].excludedSource(this, source);
-//    }
-//  }
-
-//  /**
-//   * Notify all of the analysis listeners that the given source is now included in the set of
-//   * sources that are being analyzed.
-//   *
-//   * @param source the source that is now being analyzed
-//   */
-//  void _notifyIncludedSource(Source source) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].includedSource(this, source);
-//    }
-//  }
-
-//  /**
-//   * Notify all of the analysis listeners that the given Dart source was parsed.
-//   *
-//   * @param source the source that was parsed
-//   * @param unit the result of parsing the source
-//   */
-//  void _notifyParsedDart(Source source, CompilationUnit unit) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].parsedDart(this, source, unit);
-//    }
-//  }
-
-//  /**
-//   * Notify all of the analysis listeners that the given HTML source was parsed.
-//   *
-//   * @param source the source that was parsed
-//   * @param unit the result of parsing the source
-//   */
-//  void _notifyParsedHtml(Source source, ht.HtmlUnit unit) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].parsedHtml(this, source, unit);
-//    }
-//  }
-
-//  /**
-//   * Notify all of the analysis listeners that the given Dart source was resolved.
-//   *
-//   * @param source the source that was resolved
-//   * @param unit the result of resolving the source
-//   */
-//  void _notifyResolvedDart(Source source, CompilationUnit unit) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].resolvedDart(this, source, unit);
-//    }
-//  }
-
-//  /**
-//   * Notify all of the analysis listeners that the given HTML source was resolved.
-//   *
-//   * @param source the source that was resolved
-//   * @param unit the result of resolving the source
-//   */
-//  void _notifyResolvedHtml(Source source, ht.HtmlUnit unit) {
-//    int count = _listeners.length;
-//    for (int i = 0; i < count; i++) {
-//      _listeners[i].resolvedHtml(this, source, unit);
-//    }
-//  }
-
-  /**
-   * Log the given debugging [message].
-   */
-  void _logInformation(String message) {
-    AnalysisEngine.instance.logger.logInformation(message);
-  }
-
-  /**
-   * Notify all of the analysis listeners that a task is about to be performed.
-   */
-  void _notifyAboutToPerformTask(String taskDescription) {
-    int count = _listeners.length;
-    for (int i = 0; i < count; i++) {
-      _listeners[i].aboutToPerformTask(this, taskDescription);
-    }
-  }
-
-  /**
-   * Notify all of the analysis listeners that the errors associated with the
-   * given [source] has been updated to the given [errors].
-   */
-  void _notifyErrors(
-      Source source, List<AnalysisError> errors, LineInfo lineInfo) {
-    int count = _listeners.length;
-    for (int i = 0; i < count; i++) {
-      _listeners[i].computedErrors(this, source, errors, lineInfo);
-    }
-  }
-
-  /**
-   * Given that the given [source] (with the corresponding [sourceEntry]) has
-   * been invalidated, invalidate all of the libraries that depend on it.
-   */
-  void _propagateInvalidation(Source source, SourceEntry sourceEntry) {
-    if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      htmlEntry.modificationTime = getModificationStamp(source);
-      htmlEntry.invalidateAllInformation();
-      _cache.removedAst(source);
-      _workManager.add(source, SourcePriority.HTML);
-    } else if (sourceEntry is DartEntry) {
-      List<Source> containingLibraries = getLibrariesContaining(source);
-      List<Source> dependentLibraries = getLibrariesDependingOn(source);
-      HashSet<Source> librariesToInvalidate = new HashSet<Source>();
-      for (Source containingLibrary in containingLibraries) {
-        _computeAllLibrariesDependingOn(
-            containingLibrary, librariesToInvalidate);
-      }
-      for (Source dependentLibrary in dependentLibraries) {
-        _computeAllLibrariesDependingOn(
-            dependentLibrary, librariesToInvalidate);
-      }
-      for (Source library in librariesToInvalidate) {
-        _invalidateLibraryResolution(library);
-      }
-      DartEntry dartEntry = _cache.get(source);
-      _removeFromParts(source, dartEntry);
-      dartEntry.modificationTime = getModificationStamp(source);
-      dartEntry.invalidateAllInformation();
-      _cache.removedAst(source);
-      _workManager.add(source, SourcePriority.UNKNOWN);
-    }
-    // reset unit in the notification, it is out of date now
-    ChangeNoticeImpl notice = _pendingNotices[source];
-    if (notice != null) {
-      notice.resolvedDartUnit = null;
-      notice.resolvedHtmlUnit = null;
-    }
-  }
-
-  /**
-   * Given a [dartEntry] and a [library] element, record the library element and
-   * other information gleaned from the element in the cache entry.
-   */
-  void _recordElementData(DartEntry dartEntry, LibraryElement library,
-      Source librarySource, Source htmlSource) {
-    dartEntry.setValue(DartEntry.ELEMENT, library);
-    dartEntry.setValue(DartEntry.IS_LAUNCHABLE, library.entryPoint != null);
-    dartEntry.setValue(DartEntry.IS_CLIENT,
-        _isClient(library, htmlSource, new HashSet<LibraryElement>()));
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordGenerateDartErrorsTask(GenerateDartErrorsTask task) {
-    Source source = task.source;
-    DartEntry dartEntry = _cache.get(source);
-    Source librarySource = task.libraryElement.source;
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      dartEntry.recordVerificationErrorInLibrary(
-          librarySource, thrownException);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    dartEntry.setValueInLibrary(
-        DartEntry.VERIFICATION_ERRORS, librarySource, task.errors);
-    ChangeNoticeImpl notice = getNotice(source);
-    LineInfo lineInfo = dartEntry.getValue(SourceEntry.LINE_INFO);
-    notice.setErrors(dartEntry.allErrors, lineInfo);
-    return dartEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordGenerateDartHintsTask(GenerateDartHintsTask task) {
-    Source librarySource = task.libraryElement.source;
-    CaughtException thrownException = task.exception;
-    DartEntry libraryEntry = null;
-    HashMap<Source, List<AnalysisError>> hintMap = task.hintMap;
-    if (hintMap == null) {
-      // We don't have any information about which sources to mark as invalid
-      // other than the library source.
-      DartEntry libraryEntry = _cache.get(librarySource);
-      if (thrownException == null) {
-        String message = "GenerateDartHintsTask returned a null hint map "
-            "without throwing an exception: ${librarySource.fullName}";
-        thrownException =
-            new CaughtException(new AnalysisException(message), null);
-      }
-      libraryEntry.recordHintErrorInLibrary(librarySource, thrownException);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    hintMap.forEach((Source unitSource, List<AnalysisError> hints) {
-      DartEntry dartEntry = _cache.get(unitSource);
-      if (unitSource == librarySource) {
-        libraryEntry = dartEntry;
-      }
-      if (thrownException == null) {
-        dartEntry.setValueInLibrary(DartEntry.HINTS, librarySource, hints);
-        ChangeNoticeImpl notice = getNotice(unitSource);
-        LineInfo lineInfo = dartEntry.getValue(SourceEntry.LINE_INFO);
-        notice.setErrors(dartEntry.allErrors, lineInfo);
-      } else {
-        dartEntry.recordHintErrorInLibrary(librarySource, thrownException);
-      }
-    });
-    if (thrownException != null) {
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    return libraryEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordGenerateDartLintsTask(GenerateDartLintsTask task) {
-    Source librarySource = task.libraryElement.source;
-    CaughtException thrownException = task.exception;
-    DartEntry libraryEntry = null;
-    HashMap<Source, List<AnalysisError>> lintMap = task.lintMap;
-    if (lintMap == null) {
-      // We don't have any information about which sources to mark as invalid
-      // other than the library source.
-      DartEntry libraryEntry = _cache.get(librarySource);
-      if (thrownException == null) {
-        String message = "GenerateDartLintsTask returned a null lint map "
-            "without throwing an exception: ${librarySource.fullName}";
-        thrownException =
-            new CaughtException(new AnalysisException(message), null);
-      }
-      libraryEntry.recordLintErrorInLibrary(librarySource, thrownException);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    lintMap.forEach((Source unitSource, List<AnalysisError> lints) {
-      DartEntry dartEntry = _cache.get(unitSource);
-      if (unitSource == librarySource) {
-        libraryEntry = dartEntry;
-      }
-      if (thrownException == null) {
-        dartEntry.setValueInLibrary(DartEntry.LINTS, librarySource, lints);
-        ChangeNoticeImpl notice = getNotice(unitSource);
-        LineInfo lineInfo = dartEntry.getValue(SourceEntry.LINE_INFO);
-        notice.setErrors(dartEntry.allErrors, lineInfo);
-      } else {
-        dartEntry.recordLintErrorInLibrary(librarySource, thrownException);
-      }
-    });
-    if (thrownException != null) {
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    return libraryEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  SourceEntry _recordGetContentsTask(GetContentTask task) {
-    if (!task.isComplete) {
-      return null;
-    }
-    Source source = task.source;
-    SourceEntry sourceEntry = _cache.get(source);
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      sourceEntry.recordContentError(thrownException);
-      {
-        sourceEntry.setValue(SourceEntry.CONTENT_ERRORS, task.errors);
-        ChangeNoticeImpl notice = getNotice(source);
-        notice.setErrors(sourceEntry.allErrors, null);
-      }
-      _workManager.remove(source);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    sourceEntry.modificationTime = task.modificationTime;
-    sourceEntry.setValue(SourceEntry.CONTENT, task.content);
-    return sourceEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordIncrementalAnalysisTaskResults(
-      IncrementalAnalysisTask task) {
-    CompilationUnit unit = task.compilationUnit;
-    if (unit != null) {
-      ChangeNoticeImpl notice = getNotice(task.source);
-      notice.resolvedDartUnit = unit;
-      _incrementalAnalysisCache =
-          IncrementalAnalysisCache.cacheResult(task.cache, unit);
-    }
-    return null;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordParseDartTaskResults(ParseDartTask task) {
-    Source source = task.source;
-    DartEntry dartEntry = _cache.get(source);
-    _removeFromParts(source, dartEntry);
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      _removeFromParts(source, dartEntry);
-      dartEntry.recordParseError(thrownException);
-      _cache.removedAst(source);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    if (task.hasNonPartOfDirective) {
-      dartEntry.setValue(DartEntry.SOURCE_KIND, SourceKind.LIBRARY);
-      dartEntry.containingLibrary = source;
-      _workManager.add(source, SourcePriority.LIBRARY);
-    } else if (task.hasPartOfDirective) {
-      dartEntry.setValue(DartEntry.SOURCE_KIND, SourceKind.PART);
-      dartEntry.removeContainingLibrary(source);
-      _workManager.add(source, SourcePriority.NORMAL_PART);
-    } else {
-      // The file contains no directives.
-      List<Source> containingLibraries = dartEntry.containingLibraries;
-      if (containingLibraries.length > 1 ||
-          (containingLibraries.length == 1 &&
-              containingLibraries[0] != source)) {
-        dartEntry.setValue(DartEntry.SOURCE_KIND, SourceKind.PART);
-        dartEntry.removeContainingLibrary(source);
-        _workManager.add(source, SourcePriority.NORMAL_PART);
-      } else {
-        dartEntry.setValue(DartEntry.SOURCE_KIND, SourceKind.LIBRARY);
-        dartEntry.containingLibrary = source;
-        _workManager.add(source, SourcePriority.LIBRARY);
-      }
-    }
-    List<Source> newParts = task.includedSources;
-    for (int i = 0; i < newParts.length; i++) {
-      Source partSource = newParts[i];
-      DartEntry partEntry = _getReadableDartEntry(partSource);
-      if (partEntry != null && !identical(partEntry, dartEntry)) {
-        // TODO(brianwilkerson) Change the kind of the "part" if it was marked
-        // as a library and it has no directives.
-        partEntry.addContainingLibrary(source);
-      }
-    }
-    dartEntry.setValue(DartEntry.PARSED_UNIT, task.compilationUnit);
-    dartEntry.setValue(DartEntry.PARSE_ERRORS, task.errors);
-    dartEntry.setValue(DartEntry.EXPORTED_LIBRARIES, task.exportedSources);
-    dartEntry.setValue(DartEntry.IMPORTED_LIBRARIES, task.importedSources);
-    dartEntry.setValue(DartEntry.INCLUDED_PARTS, newParts);
-    _cache.storedAst(source);
-    ChangeNoticeImpl notice = getNotice(source);
-    if (notice.resolvedDartUnit == null) {
-      notice.parsedDartUnit = task.compilationUnit;
-    }
-    notice.setErrors(dartEntry.allErrors, task.lineInfo);
-    // Verify that the incrementally parsed and resolved unit in the incremental
-    // cache is structurally equivalent to the fully parsed unit
-    _incrementalAnalysisCache = IncrementalAnalysisCache.verifyStructure(
-        _incrementalAnalysisCache, source, task.compilationUnit);
-    return dartEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  HtmlEntry _recordParseHtmlTaskResults(ParseHtmlTask task) {
-    Source source = task.source;
-    HtmlEntry htmlEntry = _cache.get(source);
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      htmlEntry.recordParseError(thrownException);
-      _cache.removedAst(source);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    LineInfo lineInfo = task.lineInfo;
-    htmlEntry.setValue(SourceEntry.LINE_INFO, lineInfo);
-    htmlEntry.setValue(HtmlEntry.PARSED_UNIT, task.htmlUnit);
-    htmlEntry.setValue(HtmlEntry.PARSE_ERRORS, task.errors);
-    htmlEntry.setValue(
-        HtmlEntry.REFERENCED_LIBRARIES, task.referencedLibraries);
-    _cache.storedAst(source);
-    ChangeNoticeImpl notice = getNotice(source);
-    notice.setErrors(htmlEntry.allErrors, lineInfo);
-    return htmlEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordResolveDartUnitTaskResults(ResolveDartUnitTask task) {
-    Source unitSource = task.source;
-    DartEntry dartEntry = _cache.get(unitSource);
-    Source librarySource = task.librarySource;
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      dartEntry.recordResolutionErrorInLibrary(librarySource, thrownException);
-      _cache.removedAst(unitSource);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    dartEntry.setValueInLibrary(
-        DartEntry.RESOLVED_UNIT, librarySource, task.resolvedUnit);
-    _cache.storedAst(unitSource);
-    return dartEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  HtmlEntry _recordResolveHtmlTaskResults(ResolveHtmlTask task) {
-    Source source = task.source;
-    HtmlEntry htmlEntry = _cache.get(source);
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      htmlEntry.recordResolutionError(thrownException);
-      _cache.removedAst(source);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    htmlEntry.setState(HtmlEntry.PARSED_UNIT, CacheState.FLUSHED);
-    htmlEntry.setValue(HtmlEntry.RESOLVED_UNIT, task.resolvedUnit);
-    htmlEntry.setValue(HtmlEntry.ELEMENT, task.element);
-    htmlEntry.setValue(HtmlEntry.RESOLUTION_ERRORS, task.resolutionErrors);
-    _cache.storedAst(source);
-    ChangeNoticeImpl notice = getNotice(source);
-    notice.resolvedHtmlUnit = task.resolvedUnit;
-    LineInfo lineInfo = htmlEntry.getValue(SourceEntry.LINE_INFO);
-    notice.setErrors(htmlEntry.allErrors, lineInfo);
-    return htmlEntry;
-  }
-
-  /**
-   * Record the results produced by performing a [task] and return the cache
-   * entry associated with the results.
-   */
-  DartEntry _recordScanDartTaskResults(ScanDartTask task) {
-    Source source = task.source;
-    DartEntry dartEntry = _cache.get(source);
-    CaughtException thrownException = task.exception;
-    if (thrownException != null) {
-      _removeFromParts(source, dartEntry);
-      dartEntry.recordScanError(thrownException);
-      _cache.removedAst(source);
-      throw new AnalysisException('<rethrow>', thrownException);
-    }
-    LineInfo lineInfo = task.lineInfo;
-    dartEntry.setValue(SourceEntry.LINE_INFO, lineInfo);
-    dartEntry.setValue(DartEntry.TOKEN_STREAM, task.tokenStream);
-    dartEntry.setValue(DartEntry.SCAN_ERRORS, task.errors);
-    _cache.storedAst(source);
-    ChangeNoticeImpl notice = getNotice(source);
-    notice.setErrors(dartEntry.allErrors, lineInfo);
-    return dartEntry;
-  }
-
-  void _removeFromCache(Source source) {
-    SourceEntry entry = _cache.remove(source);
-    if (entry != null && !entry.explicitlyAdded) {
-      _implicitAnalysisEventsController
-          .add(new ImplicitAnalysisEvent(source, false));
-    }
-  }
-
-  /**
-   * Remove the given [librarySource] from the list of containing libraries for
-   * all of the parts referenced by the given [dartEntry].
-   */
-  void _removeFromParts(Source librarySource, DartEntry dartEntry) {
-    List<Source> oldParts = dartEntry.getValue(DartEntry.INCLUDED_PARTS);
-    for (int i = 0; i < oldParts.length; i++) {
-      Source partSource = oldParts[i];
-      DartEntry partEntry = _getReadableDartEntry(partSource);
-      if (partEntry != null && !identical(partEntry, dartEntry)) {
-        partEntry.removeContainingLibrary(librarySource);
-        if (partEntry.containingLibraries.length == 0 && !exists(partSource)) {
-          _removeFromCache(partSource);
-        }
-      }
-    }
-  }
-
-  /**
-   * Remove the given libraries that are keys in the given map from the list of
-   * containing libraries for each of the parts in the corresponding value.
-   */
-  void _removeFromPartsUsingMap(HashMap<Source, List<Source>> oldPartMap) {
-    oldPartMap.forEach((Source librarySource, List<Source> oldParts) {
-      for (int i = 0; i < oldParts.length; i++) {
-        Source partSource = oldParts[i];
-        if (partSource != librarySource) {
-          DartEntry partEntry = _getReadableDartEntry(partSource);
-          if (partEntry != null) {
-            partEntry.removeContainingLibrary(librarySource);
-            if (partEntry.containingLibraries.length == 0 &&
-                !exists(partSource)) {
-              _removeFromCache(partSource);
-            }
-          }
-        }
-      }
-    });
-  }
-
-  /**
-   * Remove the given [source] from the priority order if it is in the list.
-   */
-  void _removeFromPriorityOrder(Source source) {
-    int count = _priorityOrder.length;
-    List<Source> newOrder = new List<Source>();
-    for (int i = 0; i < count; i++) {
-      if (_priorityOrder[i] != source) {
-        newOrder.add(_priorityOrder[i]);
-      }
-    }
-    if (newOrder.length < count) {
-      analysisPriorityOrder = newOrder;
-    }
-  }
-
-  /**
-   * Create an entry for the newly added [source] and invalidate any sources
-   * that referenced the source before it existed.
-   */
-  void _sourceAvailable(Source source) {
-    // TODO(brianwilkerson) This method needs to check whether the source was
-    // previously being implicitly analyzed. If so, the cache entry needs to be
-    // update to reflect the new status and an event needs to be generated to
-    // inform clients that it is no longer being implicitly analyzed.
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry == null) {
-      sourceEntry = _createSourceEntry(source, true);
-    } else {
-      _propagateInvalidation(source, sourceEntry);
-      sourceEntry = _cache.get(source);
-    }
-    if (sourceEntry is HtmlEntry) {
-      _workManager.add(source, SourcePriority.HTML);
-    } else if (sourceEntry is DartEntry) {
-      _workManager.add(source, _computePriority(sourceEntry));
-    }
-  }
-
-  /**
-   * Invalidate the [source] that was changed and any sources that referenced
-   * the source before it existed.
-   */
-  void _sourceChanged(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    // If the source is removed, we don't care about it.
-    if (sourceEntry == null) {
-      return;
-    }
-    // Check if the content of the source is the same as it was the last time.
-    String sourceContent = sourceEntry.getValue(SourceEntry.CONTENT);
-    if (sourceContent != null) {
-      sourceEntry.setState(SourceEntry.CONTENT, CacheState.FLUSHED);
-      try {
-        TimestampedData<String> fileContents = getContents(source);
-        if (fileContents.data == sourceContent) {
-          return;
-        }
-      } catch (e) {}
-    }
-    // We have to invalidate the cache.
-    _propagateInvalidation(source, sourceEntry);
-  }
-
-  /**
-   * Record that the give [source] has been deleted.
-   */
-  void _sourceDeleted(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      htmlEntry.recordContentError(new CaughtException(
-          new AnalysisException("This source was marked as being deleted"),
-          null));
-    } else if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      HashSet<Source> libraries = new HashSet<Source>();
-      for (Source librarySource in getLibrariesContaining(source)) {
-        libraries.add(librarySource);
-        for (Source dependentLibrary
-            in getLibrariesDependingOn(librarySource)) {
-          libraries.add(dependentLibrary);
-        }
-      }
-      for (Source librarySource in libraries) {
-        _invalidateLibraryResolution(librarySource);
-      }
-      dartEntry.recordContentError(new CaughtException(
-          new AnalysisException("This source was marked as being deleted"),
-          null));
-    }
-    _workManager.remove(source);
-    _removeFromPriorityOrder(source);
-  }
-
-  /**
-   * Record that the given [source] has been removed.
-   */
-  void _sourceRemoved(Source source) {
-    SourceEntry sourceEntry = _cache.get(source);
-    if (sourceEntry is HtmlEntry) {} else if (sourceEntry is DartEntry) {
-      HashSet<Source> libraries = new HashSet<Source>();
-      for (Source librarySource in getLibrariesContaining(source)) {
-        libraries.add(librarySource);
-        for (Source dependentLibrary
-            in getLibrariesDependingOn(librarySource)) {
-          libraries.add(dependentLibrary);
-        }
-      }
-      for (Source librarySource in libraries) {
-        _invalidateLibraryResolution(librarySource);
-      }
-    }
-    _removeFromCache(source);
-    _workManager.remove(source);
-    _removeFromPriorityOrder(source);
-  }
-
-  /**
-   * TODO(scheglov) A hackish, limited incremental resolution implementation.
-   */
-  bool _tryPoorMansIncrementalResolution(Source unitSource, String newCode) {
-    return PerformanceStatistics.incrementalAnalysis.makeCurrentWhile(() {
-      incrementalResolutionValidation_lastUnitSource = null;
-      incrementalResolutionValidation_lastLibrarySource = null;
-      incrementalResolutionValidation_lastUnit = null;
-      // prepare the entry
-      DartEntry dartEntry = _cache.get(unitSource);
-      if (dartEntry == null) {
-        return false;
-      }
-      // prepare the (only) library source
-      List<Source> librarySources = getLibrariesContaining(unitSource);
-      if (librarySources.length != 1) {
-        return false;
-      }
-      Source librarySource = librarySources[0];
-      // prepare the library element
-      LibraryElement libraryElement = getLibraryElement(librarySource);
-      if (libraryElement == null) {
-        return false;
-      }
-      // prepare the existing unit
-      CompilationUnit oldUnit =
-          getResolvedCompilationUnit2(unitSource, librarySource);
-      if (oldUnit == null) {
-        return false;
-      }
-      // do resolution
-      Stopwatch perfCounter = new Stopwatch()..start();
-      PoorMansIncrementalResolver resolver = new PoorMansIncrementalResolver(
-          typeProvider,
-          unitSource,
-          getReadableSourceEntryOrNull(unitSource),
-          null,
-          null,
-          oldUnit,
-          analysisOptions.incrementalApi);
-      bool success = resolver.resolve(newCode);
-      AnalysisEngine.instance.instrumentationService.logPerformance(
-          AnalysisPerformanceKind.INCREMENTAL,
-          perfCounter,
-          'success=$success,context_id=$_id,code_length=${newCode.length}');
-      if (!success) {
-        return false;
-      }
-      // if validation, remember the result, but throw it away
-      if (analysisOptions.incrementalValidation) {
-        incrementalResolutionValidation_lastUnitSource = oldUnit.element.source;
-        incrementalResolutionValidation_lastLibrarySource =
-            oldUnit.element.library.source;
-        incrementalResolutionValidation_lastUnit = oldUnit;
-        return false;
-      }
-      // prepare notice
-      {
-        LineInfo lineInfo = getLineInfo(unitSource);
-        ChangeNoticeImpl notice = getNotice(unitSource);
-        notice.resolvedDartUnit = oldUnit;
-        notice.setErrors(dartEntry.allErrors, lineInfo);
-      }
-      // OK
-      return true;
-    });
-  }
-
-  void _validateLastIncrementalResolutionResult() {
-    if (incrementalResolutionValidation_lastUnitSource == null ||
-        incrementalResolutionValidation_lastLibrarySource == null ||
-        incrementalResolutionValidation_lastUnit == null) {
-      return;
-    }
-    CompilationUnit fullUnit = getResolvedCompilationUnit2(
-        incrementalResolutionValidation_lastUnitSource,
-        incrementalResolutionValidation_lastLibrarySource);
-    if (fullUnit != null) {
-      try {
-        assertSameResolution(
-            incrementalResolutionValidation_lastUnit, fullUnit);
-      } on IncrementalResolutionMismatch catch (mismatch, stack) {
-        String failure = mismatch.message;
-        String message =
-            'Incremental resolution mismatch:\n$failure\nat\n$stack';
-        AnalysisEngine.instance.logger.logError(message);
-      }
-    }
-    incrementalResolutionValidation_lastUnitSource = null;
-    incrementalResolutionValidation_lastLibrarySource = null;
-    incrementalResolutionValidation_lastUnit = null;
-  }
-}
-
-/**
- * An object used by an analysis context to record the results of a task.
- */
-class AnalysisContextImpl_AnalysisTaskResultRecorder
-    implements AnalysisTaskVisitor<SourceEntry> {
-  final AnalysisContextImpl AnalysisContextImpl_this;
-
-  AnalysisContextImpl_AnalysisTaskResultRecorder(this.AnalysisContextImpl_this);
-
-  @override
-  DartEntry visitGenerateDartErrorsTask(GenerateDartErrorsTask task) =>
-      AnalysisContextImpl_this._recordGenerateDartErrorsTask(task);
-
-  @override
-  DartEntry visitGenerateDartHintsTask(GenerateDartHintsTask task) =>
-      AnalysisContextImpl_this._recordGenerateDartHintsTask(task);
-
-  @override
-  DartEntry visitGenerateDartLintsTask(GenerateDartLintsTask task) =>
-      AnalysisContextImpl_this._recordGenerateDartLintsTask(task);
-
-  @override
-  SourceEntry visitGetContentTask(GetContentTask task) =>
-      AnalysisContextImpl_this._recordGetContentsTask(task);
-
-  @override
-  DartEntry visitIncrementalAnalysisTask(IncrementalAnalysisTask task) =>
-      AnalysisContextImpl_this._recordIncrementalAnalysisTaskResults(task);
-
-  @override
-  DartEntry visitParseDartTask(ParseDartTask task) =>
-      AnalysisContextImpl_this._recordParseDartTaskResults(task);
-
-  @override
-  HtmlEntry visitParseHtmlTask(ParseHtmlTask task) =>
-      AnalysisContextImpl_this._recordParseHtmlTaskResults(task);
-
-  @override
-  DartEntry visitResolveDartLibraryCycleTask(
-          ResolveDartLibraryCycleTask task) =>
-      AnalysisContextImpl_this.recordResolveDartLibraryCycleTaskResults(task);
-
-  @override
-  DartEntry visitResolveDartLibraryTask(ResolveDartLibraryTask task) =>
-      AnalysisContextImpl_this.recordResolveDartLibraryTaskResults(task);
-
-  @override
-  DartEntry visitResolveDartUnitTask(ResolveDartUnitTask task) =>
-      AnalysisContextImpl_this._recordResolveDartUnitTaskResults(task);
-
-  @override
-  HtmlEntry visitResolveHtmlTask(ResolveHtmlTask task) =>
-      AnalysisContextImpl_this._recordResolveHtmlTaskResults(task);
-
-  @override
-  DartEntry visitScanDartTask(ScanDartTask task) =>
-      AnalysisContextImpl_this._recordScanDartTaskResults(task);
-}
-
-class AnalysisContextImpl_ContextRetentionPolicy
-    implements CacheRetentionPolicy {
-  final AnalysisContextImpl AnalysisContextImpl_this;
-
-  AnalysisContextImpl_ContextRetentionPolicy(this.AnalysisContextImpl_this);
-
-  @override
-  RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry) {
-    int priorityCount = AnalysisContextImpl_this._priorityOrder.length;
-    for (int i = 0; i < priorityCount; i++) {
-      if (source == AnalysisContextImpl_this._priorityOrder[i]) {
-        return RetentionPriority.HIGH;
-      }
-    }
-    if (AnalysisContextImpl_this._neededForResolution != null &&
-        AnalysisContextImpl_this._neededForResolution.contains(source)) {
-      return RetentionPriority.HIGH;
-    }
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      if (_astIsNeeded(dartEntry)) {
-        return RetentionPriority.MEDIUM;
-      }
-    }
-    return RetentionPriority.LOW;
-  }
-
-  bool _astIsNeeded(DartEntry dartEntry) =>
-      dartEntry.hasInvalidData(DartEntry.HINTS) ||
-          dartEntry.hasInvalidData(DartEntry.LINTS) ||
-          dartEntry.hasInvalidData(DartEntry.VERIFICATION_ERRORS) ||
-          dartEntry.hasInvalidData(DartEntry.RESOLUTION_ERRORS);
-}
-
-/**
- * An object used to construct a list of the libraries that must be resolved
- * together in order to resolve any one of the libraries.
- */
-class AnalysisContextImpl_CycleBuilder {
-  final AnalysisContextImpl AnalysisContextImpl_this;
-
-  /**
-   * A table mapping the sources of the defining compilation units of libraries
-   * to the representation of the library that has the information needed to
-   * resolve the library.
-   */
-  HashMap<Source, ResolvableLibrary> _libraryMap =
-      new HashMap<Source, ResolvableLibrary>();
-
-  /**
-   * The dependency graph used to compute the libraries in the cycle.
-   */
-  DirectedGraph<ResolvableLibrary> _dependencyGraph;
-
-  /**
-   * A list containing the libraries that are ready to be resolved.
-   */
-  List<ResolvableLibrary> _librariesInCycle;
-
-  /**
-   * The analysis task that needs to be performed before the cycle of libraries
-   * can be resolved, or `null` if the libraries are ready to be resolved.
-   */
-  AnalysisContextImpl_TaskData _taskData;
-
-  /**
-   * Initialize a newly created cycle builder.
-   */
-  AnalysisContextImpl_CycleBuilder(this.AnalysisContextImpl_this) : super();
-
-  /**
-   * Return a list containing the libraries that are ready to be resolved
-   * (assuming that [getTaskData] returns `null`).
-   */
-  List<ResolvableLibrary> get librariesInCycle => _librariesInCycle;
-
-  /**
-   * Return a representation of an analysis task that needs to be performed
-   * before the cycle of libraries can be resolved, or `null` if the libraries
-   * are ready to be resolved.
-   */
-  AnalysisContextImpl_TaskData get taskData => _taskData;
-
-  /**
-   * Compute a list of the libraries that need to be resolved together in orde
-   *  to resolve the given [librarySource].
-   */
-  void computeCycleContaining(Source librarySource) {
-    //
-    // Create the object representing the library being resolved.
-    //
-    ResolvableLibrary targetLibrary = _createLibrary(librarySource);
-    //
-    // Compute the set of libraries that need to be resolved together.
-    //
-    _dependencyGraph = new DirectedGraph<ResolvableLibrary>();
-    _computeLibraryDependencies(targetLibrary);
-    if (_taskData != null) {
-      return;
-    }
-    _librariesInCycle = _dependencyGraph.findCycleContaining(targetLibrary);
-    //
-    // Ensure that all of the data needed to resolve them has been computed.
-    //
-    _ensureImportsAndExports();
-    if (_taskData != null) {
-      // At least one imported library needs to be resolved before the target
-      // library.
-      AnalysisTask task = _taskData.task;
-      if (task is ResolveDartLibraryTask) {
-        AnalysisContextImpl_this._workManager
-            .addFirst(task.librarySource, SourcePriority.LIBRARY);
-      }
-      return;
-    }
-    _computePartsInCycle(librarySource);
-    if (_taskData != null) {
-      // At least one part needs to be parsed.
-      return;
-    }
-    // All of the AST's necessary to perform a resolution of the library cycle
-    // have been gathered, so it is no longer necessary to retain them in the
-    // cache.
-    AnalysisContextImpl_this._neededForResolution = null;
-  }
-
-  bool _addDependency(ResolvableLibrary dependant, Source dependency,
-      List<ResolvableLibrary> dependencyList) {
-    if (dependant.librarySource == dependency) {
-      // Don't add a dependency of a library on itself; there's no point.
-      return true;
-    }
-    ResolvableLibrary importedLibrary = _libraryMap[dependency];
-    if (importedLibrary == null) {
-      importedLibrary = _createLibraryOrNull(dependency);
-      if (importedLibrary != null) {
-        _computeLibraryDependencies(importedLibrary);
-        if (_taskData != null) {
-          return false;
-        }
-      }
-    }
-    if (importedLibrary != null) {
-      if (dependencyList != null) {
-        dependencyList.add(importedLibrary);
-      }
-      _dependencyGraph.addEdge(dependant, importedLibrary);
-    }
-    return true;
-  }
-
-  /**
-   * Recursively traverse the libraries reachable from the given [library],
-   * creating instances of the class [Library] to represent them, and record the
-   * references in the library objects.
-   *
-   * Throws an [AnalysisException] if some portion of the library graph could
-   * not be traversed.
-   */
-  void _computeLibraryDependencies(ResolvableLibrary library) {
-    Source librarySource = library.librarySource;
-    DartEntry dartEntry =
-        AnalysisContextImpl_this._getReadableDartEntry(librarySource);
-    List<Source> importedSources =
-        _getSources(librarySource, dartEntry, DartEntry.IMPORTED_LIBRARIES);
-    if (_taskData != null) {
-      return;
-    }
-    List<Source> exportedSources =
-        _getSources(librarySource, dartEntry, DartEntry.EXPORTED_LIBRARIES);
-    if (_taskData != null) {
-      return;
-    }
-    _computeLibraryDependenciesFromDirectives(
-        library, importedSources, exportedSources);
-  }
-
-  /**
-   * Recursively traverse the libraries reachable from the given [library],
-   * creating instances of the class [Library] to represent them, and record the
-   * references in the library objects. The [importedSources] is a list
-   * containing the sources that are imported into the given library. The
-   * [exportedSources] is a list containing the sources that are exported from
-   * the given library.
-   */
-  void _computeLibraryDependenciesFromDirectives(ResolvableLibrary library,
-      List<Source> importedSources, List<Source> exportedSources) {
-    int importCount = importedSources.length;
-    List<ResolvableLibrary> importedLibraries = new List<ResolvableLibrary>();
-    bool explicitlyImportsCore = false;
-    bool importsAsync = false;
-    for (int i = 0; i < importCount; i++) {
-      Source importedSource = importedSources[i];
-      if (importedSource == AnalysisContextImpl_this._coreLibrarySource) {
-        explicitlyImportsCore = true;
-      } else if (importedSource ==
-          AnalysisContextImpl_this._asyncLibrarySource) {
-        importsAsync = true;
-      }
-      if (!_addDependency(library, importedSource, importedLibraries)) {
-        return;
-      }
-    }
-    library.explicitlyImportsCore = explicitlyImportsCore;
-    if (!explicitlyImportsCore) {
-      if (!_addDependency(library, AnalysisContextImpl_this._coreLibrarySource,
-          importedLibraries)) {
-        return;
-      }
-    }
-    if (!importsAsync) {
-      // Add a dependency on async to ensure that the Future element will be
-      // built before we generate errors and warnings for async methods.  Also
-      // include it in importedLibraries, so that it will be picked up by
-      // LibraryResolver2._buildLibraryMap().
-      // TODO(paulberry): this is a bit of a hack, since the async library
-      // isn't actually being imported.  Also, it's not clear whether it should
-      // be necessary: in theory, dart:core already (indirectly) imports
-      // dart:async, so if core has been built, async should have been built
-      // too.  However, removing this code causes unit test failures.
-      if (!_addDependency(library, AnalysisContextImpl_this._asyncLibrarySource,
-          importedLibraries)) {
-        return;
-      }
-    }
-    library.importedLibraries = importedLibraries;
-    int exportCount = exportedSources.length;
-    if (exportCount > 0) {
-      List<ResolvableLibrary> exportedLibraries = new List<ResolvableLibrary>();
-      for (int i = 0; i < exportCount; i++) {
-        Source exportedSource = exportedSources[i];
-        if (!_addDependency(library, exportedSource, exportedLibraries)) {
-          return;
-        }
-      }
-      library.exportedLibraries = exportedLibraries;
-    }
-  }
-
-  /**
-   * Gather the resolvable AST structures for each of the compilation units in
-   * each of the libraries in the cycle. This is done in two phases: first we
-   * ensure that we have cached an AST structure for each compilation unit, then
-   * we gather them. We split the work this way because getting the AST
-   * structures can change the state of the cache in such a way that we would
-   * have more work to do if any compilation unit didn't have a resolvable AST
-   * structure.
-   */
-  void _computePartsInCycle(Source librarySource) {
-    int count = _librariesInCycle.length;
-    List<CycleBuilder_LibraryPair> libraryData =
-        new List<CycleBuilder_LibraryPair>();
-    for (int i = 0; i < count; i++) {
-      ResolvableLibrary library = _librariesInCycle[i];
-      libraryData.add(new CycleBuilder_LibraryPair(
-          library, _ensurePartsInLibrary(library)));
-    }
-    AnalysisContextImpl_this._neededForResolution = _gatherSources(libraryData);
-    if (AnalysisContextImpl._TRACE_PERFORM_TASK) {
-      print(
-          "  preserve resolution data for ${AnalysisContextImpl_this._neededForResolution.length} sources while resolving ${librarySource.fullName}");
-    }
-    if (_taskData != null) {
-      return;
-    }
-    for (int i = 0; i < count; i++) {
-      _computePartsInLibrary(libraryData[i]);
-    }
-  }
-
-  /**
-   * Gather the resolvable compilation units for each of the compilation units
-   * in the library represented by the [libraryPair].
-   */
-  void _computePartsInLibrary(CycleBuilder_LibraryPair libraryPair) {
-    ResolvableLibrary library = libraryPair.library;
-    List<CycleBuilder_SourceEntryPair> entryPairs = libraryPair.entryPairs;
-    int count = entryPairs.length;
-    List<ResolvableCompilationUnit> units =
-        new List<ResolvableCompilationUnit>(count);
-    for (int i = 0; i < count; i++) {
-      CycleBuilder_SourceEntryPair entryPair = entryPairs[i];
-      Source source = entryPair.source;
-      DartEntry dartEntry = entryPair.entry;
-      units[i] = new ResolvableCompilationUnit(
-          source, dartEntry.resolvableCompilationUnit);
-    }
-    library.resolvableCompilationUnits = units;
-  }
-
-  /**
-   * Create an object to represent the information about the library defined by
-   * the compilation unit with the given [librarySource].
-   */
-  ResolvableLibrary _createLibrary(Source librarySource) {
-    ResolvableLibrary library = new ResolvableLibrary(librarySource);
-    SourceEntry sourceEntry =
-        AnalysisContextImpl_this._cache.get(librarySource);
-    if (sourceEntry is DartEntry) {
-      LibraryElementImpl libraryElement =
-          sourceEntry.getValue(DartEntry.ELEMENT) as LibraryElementImpl;
-      if (libraryElement != null) {
-        library.libraryElement = libraryElement;
-      }
-    }
-    _libraryMap[librarySource] = library;
-    return library;
-  }
-
-  /**
-   * Create an object to represent the information about the library defined by
-   * the compilation unit with the given [librarySource].
-   */
-  ResolvableLibrary _createLibraryOrNull(Source librarySource) {
-    ResolvableLibrary library = new ResolvableLibrary(librarySource);
-    SourceEntry sourceEntry =
-        AnalysisContextImpl_this._cache.get(librarySource);
-    if (sourceEntry is DartEntry) {
-      LibraryElementImpl libraryElement =
-          sourceEntry.getValue(DartEntry.ELEMENT) as LibraryElementImpl;
-      if (libraryElement != null) {
-        library.libraryElement = libraryElement;
-      }
-    }
-    _libraryMap[librarySource] = library;
-    return library;
-  }
-
-  /**
-   * Ensure that the given [library] has an element model built for it. If
-   * another task needs to be executed first in order to build the element
-   * model, that task is placed in [taskData].
-   */
-  void _ensureElementModel(ResolvableLibrary library) {
-    Source librarySource = library.librarySource;
-    DartEntry libraryEntry =
-        AnalysisContextImpl_this._getReadableDartEntry(librarySource);
-    if (libraryEntry != null &&
-        libraryEntry.getState(DartEntry.PARSED_UNIT) != CacheState.ERROR) {
-      AnalysisContextImpl_this._workManager
-          .addFirst(librarySource, SourcePriority.LIBRARY);
-      if (_taskData == null) {
-        _taskData = AnalysisContextImpl_this._createResolveDartLibraryTask(
-            librarySource, libraryEntry);
-      }
-    }
-  }
-
-  /**
-   * Ensure that all of the libraries that are exported by the given [library]
-   * (but are not themselves in the cycle) have element models built for them.
-   * If another task needs to be executed first in order to build the element
-   * model, that task is placed in [taskData].
-   */
-  void _ensureExports(
-      ResolvableLibrary library, HashSet<Source> visitedLibraries) {
-    List<ResolvableLibrary> dependencies = library.exports;
-    int dependencyCount = dependencies.length;
-    for (int i = 0; i < dependencyCount; i++) {
-      ResolvableLibrary dependency = dependencies[i];
-      if (!_librariesInCycle.contains(dependency) &&
-          visitedLibraries.add(dependency.librarySource)) {
-        if (dependency.libraryElement == null) {
-          _ensureElementModel(dependency);
-        } else {
-          _ensureExports(dependency, visitedLibraries);
-        }
-        if (_taskData != null) {
-          return;
-        }
-      }
-    }
-  }
-
-  /**
-   * Ensure that all of the libraries that are exported by the given [library]
-   * (but are not themselves in the cycle) have element models built for them.
-   * If another task needs to be executed first in order to build the element
-   * model, that task is placed in [taskData].
-   */
-  void _ensureImports(ResolvableLibrary library) {
-    List<ResolvableLibrary> dependencies = library.imports;
-    int dependencyCount = dependencies.length;
-    for (int i = 0; i < dependencyCount; i++) {
-      ResolvableLibrary dependency = dependencies[i];
-      if (!_librariesInCycle.contains(dependency) &&
-          dependency.libraryElement == null) {
-        _ensureElementModel(dependency);
-        if (_taskData != null) {
-          return;
-        }
-      }
-    }
-  }
-
-  /**
-   * Ensure that all of the libraries that are either imported or exported by
-   * libraries in the cycle (but are not themselves in the cycle) have element
-   * models built for them.
-   */
-  void _ensureImportsAndExports() {
-    HashSet<Source> visitedLibraries = new HashSet<Source>();
-    int libraryCount = _librariesInCycle.length;
-    for (int i = 0; i < libraryCount; i++) {
-      ResolvableLibrary library = _librariesInCycle[i];
-      _ensureImports(library);
-      if (_taskData != null) {
-        return;
-      }
-      _ensureExports(library, visitedLibraries);
-      if (_taskData != null) {
-        return;
-      }
-    }
-  }
-
-  /**
-   * Ensure that there is a resolvable compilation unit available for all of the
-   * compilation units in the given [library].
-   */
-  List<CycleBuilder_SourceEntryPair> _ensurePartsInLibrary(
-      ResolvableLibrary library) {
-    List<CycleBuilder_SourceEntryPair> pairs =
-        new List<CycleBuilder_SourceEntryPair>();
-    Source librarySource = library.librarySource;
-    DartEntry libraryEntry =
-        AnalysisContextImpl_this._getReadableDartEntry(librarySource);
-    if (libraryEntry == null) {
-      throw new AnalysisException(
-          "Cannot find entry for ${librarySource.fullName}");
-    } else if (libraryEntry.getState(DartEntry.PARSED_UNIT) ==
-        CacheState.ERROR) {
-      String message =
-          "Cannot compute parsed unit for ${librarySource.fullName}";
-      CaughtException exception = libraryEntry.exception;
-      if (exception == null) {
-        throw new AnalysisException(message);
-      }
-      throw new AnalysisException(
-          message, new CaughtException(exception, null));
-    }
-    _ensureResolvableCompilationUnit(librarySource, libraryEntry);
-    pairs.add(new CycleBuilder_SourceEntryPair(librarySource, libraryEntry));
-    List<Source> partSources =
-        _getSources(librarySource, libraryEntry, DartEntry.INCLUDED_PARTS);
-    int count = partSources.length;
-    for (int i = 0; i < count; i++) {
-      Source partSource = partSources[i];
-      DartEntry partEntry =
-          AnalysisContextImpl_this._getReadableDartEntry(partSource);
-      if (partEntry != null &&
-          partEntry.getState(DartEntry.PARSED_UNIT) != CacheState.ERROR) {
-        _ensureResolvableCompilationUnit(partSource, partEntry);
-        pairs.add(new CycleBuilder_SourceEntryPair(partSource, partEntry));
-      }
-    }
-    return pairs;
-  }
-
-  /**
-   * Ensure that there is a resolvable compilation unit available for the given
-   * [source].
-   */
-  void _ensureResolvableCompilationUnit(Source source, DartEntry dartEntry) {
-    // The entry will be null if the source represents a non-Dart file.
-    if (dartEntry != null && !dartEntry.hasResolvableCompilationUnit) {
-      if (_taskData == null) {
-        _taskData =
-            AnalysisContextImpl_this._createParseDartTask(source, dartEntry);
-      }
-    }
-  }
-
-  HashSet<Source> _gatherSources(List<CycleBuilder_LibraryPair> libraryData) {
-    int libraryCount = libraryData.length;
-    HashSet<Source> sources = new HashSet<Source>();
-    for (int i = 0; i < libraryCount; i++) {
-      List<CycleBuilder_SourceEntryPair> entryPairs = libraryData[i].entryPairs;
-      int entryCount = entryPairs.length;
-      for (int j = 0; j < entryCount; j++) {
-        sources.add(entryPairs[j].source);
-      }
-    }
-    return sources;
-  }
-
-  /**
-   * Return the sources described by the given [descriptor].
-   */
-  List<Source> _getSources(Source source, DartEntry dartEntry,
-      DataDescriptor<List<Source>> descriptor) {
-    if (dartEntry == null) {
-      return Source.EMPTY_LIST;
-    }
-    CacheState exportState = dartEntry.getState(descriptor);
-    if (exportState == CacheState.ERROR) {
-      return Source.EMPTY_LIST;
-    } else if (exportState != CacheState.VALID) {
-      if (_taskData == null) {
-        _taskData =
-            AnalysisContextImpl_this._createParseDartTask(source, dartEntry);
-      }
-      return Source.EMPTY_LIST;
-    }
-    return dartEntry.getValue(descriptor);
-  }
-}
-
-/**
- * Information about the next task to be performed. Each data has an implicit
- * associated source: the source that might need to be analyzed. There are
- * essentially three states that can be represented:
- *
- * * If [getTask] returns a non-`null` value, then that is the task that should
- *   be executed to further analyze the associated source.
- * * Otherwise, if [isBlocked] returns `true`, then there is no work that can be
- *   done, but analysis for the associated source is not complete.
- * * Otherwise, [getDependentSource] should return a source that needs to be
- *   analyzed before the analysis of the associated source can be completed.
- */
-class AnalysisContextImpl_TaskData {
-  /**
-   * The task that is to be performed.
-   */
-  final AnalysisTask task;
-
-  /**
-   * A flag indicating whether the associated source is blocked waiting for its
-   * contents to be loaded.
-   */
-  final bool _blocked;
-
-  /**
-   * Initialize a newly created data holder.
-   */
-  AnalysisContextImpl_TaskData(this.task, this._blocked);
-
-  /**
-   * Return `true` if the associated source is blocked waiting for its contents
-   * to be loaded.
-   */
-  bool get isBlocked => _blocked;
-
-  @override
-  String toString() {
-    if (task == null) {
-      return "blocked: $_blocked";
-    }
-    return task.toString();
-  }
-}
-
-/**
- * Statistics and information about a single [AnalysisContext].
- */
-abstract class AnalysisContextStatistics {
-  /**
-   * Return the statistics for each kind of cached data.
-   */
-  List<AnalysisContextStatistics_CacheRow> get cacheRows;
-
-  /**
-   * Return the exceptions that caused some entries to have a state of
-   * [CacheState.ERROR].
-   */
-  List<CaughtException> get exceptions;
-
-  /**
-   * Return information about each of the partitions in the cache.
-   */
-  List<AnalysisContextStatistics_PartitionData> get partitionData;
-
-  /**
-   * Return a list containing all of the sources in the cache.
-   */
-  List<Source> get sources;
-}
-
-/**
- * Information about single piece of data in the cache.
- */
-abstract class AnalysisContextStatistics_CacheRow {
-  /**
-   * List of possible states which can be queried.
-   */
-  static const List<CacheState> STATES = const <CacheState>[
-    CacheState.ERROR,
-    CacheState.FLUSHED,
-    CacheState.IN_PROCESS,
-    CacheState.INVALID,
-    CacheState.VALID
-  ];
-
-  /**
-   * Return the number of entries whose state is [CacheState.ERROR].
-   */
-  int get errorCount;
-
-  /**
-   * Return the number of entries whose state is [CacheState.FLUSHED].
-   */
-  int get flushedCount;
-
-  /**
-   * Return the number of entries whose state is [CacheState.IN_PROCESS].
-   */
-  int get inProcessCount;
-
-  /**
-   * Return the number of entries whose state is [CacheState.INVALID].
-   */
-  int get invalidCount;
-
-  /**
-   * Return the name of the data represented by this object.
-   */
-  String get name;
-
-  /**
-   * Return the number of entries whose state is [CacheState.VALID].
-   */
-  int get validCount;
-
-  /**
-   * Return the number of entries whose state is [state].
-   */
-  int getCount(CacheState state);
-}
-
-/**
- * Information about a single partition in the cache.
- */
-abstract class AnalysisContextStatistics_PartitionData {
-  /**
-   * Return the number of entries in the partition that have an AST structure in
-   * one state or another.
-   */
-  int get astCount;
-
-  /**
-   * Return the total number of entries in the partition.
-   */
-  int get totalCount;
-}
-
-/**
- * Implementation of the [AnalysisContextStatistics].
- */
-class AnalysisContextStatisticsImpl implements AnalysisContextStatistics {
-  Map<String, AnalysisContextStatistics_CacheRow> _dataMap =
-      new HashMap<String, AnalysisContextStatistics_CacheRow>();
-
-  List<Source> _sources = new List<Source>();
-
-  HashSet<CaughtException> _exceptions = new HashSet<CaughtException>();
-
-  List<AnalysisContextStatistics_PartitionData> _partitionData;
-
-  @override
-  List<AnalysisContextStatistics_CacheRow> get cacheRows =>
-      _dataMap.values.toList();
-
-  @override
-  List<CaughtException> get exceptions => new List.from(_exceptions);
-
-  @override
-  List<AnalysisContextStatistics_PartitionData> get partitionData =>
-      _partitionData;
-
-  /**
-   * Set the partition data returned by this object to the given data.
-   */
-  void set partitionData(List<AnalysisContextStatistics_PartitionData> data) {
-    _partitionData = data;
-  }
-
-  @override
-  List<Source> get sources => _sources;
-
-  void addSource(Source source) {
-    _sources.add(source);
-  }
-
-  void _internalPutCacheItem(Source source, SourceEntry dartEntry,
-      DataDescriptor rowDesc, CacheState state) {
-    String rowName = rowDesc.toString();
-    AnalysisContextStatisticsImpl_CacheRowImpl row =
-        _dataMap[rowName] as AnalysisContextStatisticsImpl_CacheRowImpl;
-    if (row == null) {
-      row = new AnalysisContextStatisticsImpl_CacheRowImpl(rowName);
-      _dataMap[rowName] = row;
-    }
-    row._incState(state);
-    if (state == CacheState.ERROR) {
-      CaughtException exception = dartEntry.exception;
-      if (exception != null) {
-        _exceptions.add(exception);
-      }
-    }
-  }
-}
-
-class AnalysisContextStatisticsImpl_CacheRowImpl
-    implements AnalysisContextStatistics_CacheRow {
-  final String name;
-
-  Map<CacheState, int> _counts = <CacheState, int>{};
-
-  AnalysisContextStatisticsImpl_CacheRowImpl(this.name);
-
-  @override
-  int get errorCount => getCount(CacheState.ERROR);
-
-  @override
-  int get flushedCount => getCount(CacheState.FLUSHED);
-
-  @override
-  int get hashCode => name.hashCode;
-
-  @override
-  int get inProcessCount => getCount(CacheState.IN_PROCESS);
-
-  @override
-  int get invalidCount => getCount(CacheState.INVALID);
-
-  @override
-  int get validCount => getCount(CacheState.VALID);
-
-  @override
-  bool operator ==(Object obj) =>
-      obj is AnalysisContextStatisticsImpl_CacheRowImpl && obj.name == name;
-
-  @override
-  int getCount(CacheState state) {
-    int count = _counts[state];
-    if (count != null) {
-      return count;
-    } else {
-      return 0;
-    }
-  }
-
-  void _incState(CacheState state) {
-    if (_counts[state] == null) {
-      _counts[state] = 1;
-    } else {
-      _counts[state]++;
-    }
-  }
-}
-
-class AnalysisContextStatisticsImpl_PartitionDataImpl
-    implements AnalysisContextStatistics_PartitionData {
-  final int astCount;
-
-  final int totalCount;
-
-  AnalysisContextStatisticsImpl_PartitionDataImpl(
-      this.astCount, this.totalCount);
-}
-
-/**
  * A representation of changes to the types of analysis that should be
  * performed.
  */
 class AnalysisDelta {
   /**
    * A mapping from source to what type of analysis should be performed on that
    * source.
    */
   HashMap<Source, AnalysisLevel> _analysisMap =
       new HashMap<Source, AnalysisLevel>();
@@ skipping 122 matching lines @@
    */
   InstrumentationService _instrumentationService =
       InstrumentationService.NULL_SERVICE;
 
   /**
    * The partition manager being used to manage the shared partitions.
    */
   final PartitionManager partitionManager = new PartitionManager();
 
   /**
-   * The partition manager being used to manage the shared partitions.
-   */
-  final newContext.PartitionManager partitionManager_new =
-      new newContext.PartitionManager();
-
-  /**
-   * A flag indicating whether the (new) task model should be used to perform
-   * analysis.
-   */
-  bool useTaskModel = true;
-
-  /**
    * A flag indicating whether the task model should attempt to limit
    * invalidation after a change.
    */
   bool limitInvalidationInTaskModel = false;
 
   /**
    * The task manager used to manage the tasks used to analyze code.
    */
   TaskManager _taskManager;
 
@@ skipping 61 matching lines @@
    * will be performed the next time an analysis context is created.
    */
   void clearCaches() {
     partitionManager.clearCache();
   }
 
   /**
    * Create and return a new context in which analysis can be performed.
    */
   AnalysisContext createAnalysisContext() {
-    if (useTaskModel) {
-      return new newContext.AnalysisContextImpl();
-    }
     return new AnalysisContextImpl();
   }
 
   /**
    * A utility method that clients can use to process all of the required
    * plugins. This method can only be used by clients that do not need to
    * process any other plugins.
    */
   void processRequiredPlugins() {
     ExtensionManager manager = new ExtensionManager();
@@ skipping 602 matching lines @@
   List<ChangeNotice> get changeNotices => _notices;
 
   /**
    * Return `true` if there is more to be performed after the task that was
    * performed.
    */
   bool get hasMoreWork => _notices != null;
 }
 
 /**
- * An analysis task.
- */
-abstract class AnalysisTask {
-  /**
-   * The context in which the task is to be performed.
-   */
-  final InternalAnalysisContext context;
-
-  /**
-   * The exception that was thrown while performing this task, or `null` if the
-   * task completed successfully.
-   */
-  CaughtException _thrownException;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given
-   * [context].
-   */
-  AnalysisTask(this.context);
-
-  /**
-   * Return the exception that was thrown while performing this task, or `null`
-   * if the task completed successfully.
-   */
-  CaughtException get exception => _thrownException;
-
-  /**
-   * Return a textual description of this task.
-   */
-  String get taskDescription;
-
-  /**
-   * Use the given [visitor] to visit this task. Throws an [AnalysisException]
-   * if the visitor throws the exception.
-   */
-  accept(AnalysisTaskVisitor visitor);
-
-  /**
-   * Perform this analysis task, protected by an exception handler. Throws an
-   * [AnalysisException] if an exception occurs while performing the task.
-   */
-  void internalPerform();
-
-  /**
-   * Perform this analysis task and use the given [visitor] to visit this task
-   * after it has completed. Throws an [AnalysisException] if the visitor throws
-   * the exception.
-   */
-  Object perform(AnalysisTaskVisitor visitor) {
-    try {
-      _safelyPerform();
-    } on AnalysisException catch (exception, stackTrace) {
-      _thrownException = new CaughtException(exception, stackTrace);
-      AnalysisEngine.instance.logger.logInformation(
-          "Task failed: $taskDescription",
-          new CaughtException(exception, stackTrace));
-    }
-    return PerformanceStatistics.analysisTaskVisitor
-        .makeCurrentWhile(() => accept(visitor));
-  }
-
-  @override
-  String toString() => taskDescription;
-
-  /**
-   * Perform this analysis task, ensuring that all exceptions are wrapped in an
-   * [AnalysisException]. Throws an [AnalysisException] if any exception occurs
-   * while performing the task
-   */
-  void _safelyPerform() {
-    try {
-      String contextName = context.name;
-      if (contextName == null) {
-        contextName = 'unnamed';
-      }
-      AnalysisEngine.instance.instrumentationService
-          .logAnalysisTask(contextName, taskDescription);
-      internalPerform();
-    } on AnalysisException {
-      rethrow;
-    } catch (exception, stackTrace) {
-      throw new AnalysisException(
-          exception.toString(), new CaughtException(exception, stackTrace));
-    }
-  }
-}
-
-/**
- * An object used to visit tasks. While tasks are not structured in any
- * interesting way, this class provides the ability to dispatch to an
- * appropriate method.
- */
-abstract class AnalysisTaskVisitor<E> {
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitGenerateDartErrorsTask(GenerateDartErrorsTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitGenerateDartHintsTask(GenerateDartHintsTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitGenerateDartLintsTask(GenerateDartLintsTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitGetContentTask(GetContentTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitIncrementalAnalysisTask(
-      IncrementalAnalysisTask incrementalAnalysisTask);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitParseDartTask(ParseDartTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitParseHtmlTask(ParseHtmlTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitResolveDartLibraryCycleTask(ResolveDartLibraryCycleTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitResolveDartLibraryTask(ResolveDartLibraryTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitResolveDartUnitTask(ResolveDartUnitTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitResolveHtmlTask(ResolveHtmlTask task);
-
-  /**
-   * Visit the given [task], returning the result of the visit. This method will
-   * throw an AnalysisException if the visitor throws an exception.
-   */
-  E visitScanDartTask(ScanDartTask task);
-}
-
-/**
  * The result of applying a [ChangeSet] to a [AnalysisContext].
  */
 class ApplyChangesStatus {
   /**
    * Is `true` if the given [ChangeSet] caused any changes in the context.
    */
   final bool hasChanges;
 
   ApplyChangesStatus(this.hasChanges);
 }
 
 /**
- * A `CachedResult` is a single analysis result that is stored in a
- * [SourceEntry].
- */
-class CachedResult<E> {
-  /**
-   * The state of the cached value.
-   */
-  CacheState state;
-
-  /**
-   * The value being cached, or `null` if there is no value (for example, when
-   * the [state] is [CacheState.INVALID].
-   */
-  E value;
-
-  /**
-   * Initialize a newly created result holder to represent the value of data
-   * described by the given [descriptor].
-   */
-  CachedResult(DataDescriptor descriptor) {
-    state = CacheState.INVALID;
-    value = descriptor.defaultValue;
-  }
-}
-
-/**
- * A single partition in an LRU cache of information related to analysis.
- */
-abstract class CachePartition {
-  /**
-   * The context that owns this partition. Multiple contexts can reference a
-   * partition, but only one context can own it.
-   */
-  final InternalAnalysisContext context;
-
-  /**
-   * The maximum number of sources for which AST structures should be kept in
-   * the cache.
-   */
-  int _maxCacheSize = 0;
-
-  /**
-   * The policy used to determine which pieces of data to remove from the cache.
-   */
-  final CacheRetentionPolicy _retentionPolicy;
-
-  /**
-   * A table mapping the sources belonging to this partition to the information
-   * known about those sources.
-   */
-  HashMap<Source, SourceEntry> _sourceMap = new HashMap<Source, SourceEntry>();
-
-  /**
-   * A list containing the most recently accessed sources with the most recently
-   * used at the end of the list. When more sources are added than the maximum
-   * allowed then the least recently used source will be removed and will have
-   * it's cached AST structure flushed.
-   */
-  List<Source> _recentlyUsed;
-
-  /**
-   * Initialize a newly created cache to maintain at most [maxCacheSize] AST
-   * structures in the cache. The cache is owned by the give [context], and the
-   * [retentionPolicy] will be used to determine which pieces of data to remove
-   * from the cache.
-   */
-  CachePartition(this.context, this._maxCacheSize, this._retentionPolicy) {
-    _recentlyUsed = new List<Source>();
-  }
-
-  /**
-   * Return the number of entries in this partition that have an AST associated
-   * with them.
-   */
-  int get astSize {
-    int astSize = 0;
-    int count = _recentlyUsed.length;
-    for (int i = 0; i < count; i++) {
-      Source source = _recentlyUsed[i];
-      SourceEntry sourceEntry = _sourceMap[source];
-      if (sourceEntry is DartEntry) {
-        if (sourceEntry.anyParsedCompilationUnit != null) {
-          astSize++;
-        }
-      } else if (sourceEntry is HtmlEntry) {
-        if (sourceEntry.anyParsedUnit != null) {
-          astSize++;
-        }
-      }
-    }
-    return astSize;
-  }
-
-  /**
-   * Return a table mapping the sources known to the context to the information
-   * known about the source.
-   *
-   * <b>Note:</b> This method is only visible for use by [AnalysisCache] and
-   * should not be used for any other purpose.
-   */
-  Map<Source, SourceEntry> get map => _sourceMap;
-
-  /**
-   * Set the maximum size of the cache to the given [size].
-   */
-  void set maxCacheSize(int size) {
-    _maxCacheSize = size;
-    while (_recentlyUsed.length > _maxCacheSize) {
-      if (!_flushAstFromCache()) {
-        break;
-      }
-    }
-  }
-
-  /**
-   * Record that the AST associated with the given source was just read from the
-   * cache.
-   */
-  void accessedAst(Source source) {
-    if (_recentlyUsed.remove(source)) {
-      _recentlyUsed.add(source);
-      return;
-    }
-    while (_recentlyUsed.length >= _maxCacheSize) {
-      if (!_flushAstFromCache()) {
-        break;
-      }
-    }
-    _recentlyUsed.add(source);
-  }
-
-  /**
-   * Return `true` if the given [source] is contained in this partition.
-   */
-  bool contains(Source source);
-
-  /**
-   * Return the entry associated with the given [source].
-   */
-  SourceEntry get(Source source) => _sourceMap[source];
-
-  /**
-   * Return an iterator returning all of the map entries mapping sources to
-   * cache entries.
-   */
-  MapIterator<Source, SourceEntry> iterator() =>
-      new SingleMapIterator<Source, SourceEntry>(_sourceMap);
-
-  /**
-   * Associate the given [entry] with the given [source].
-   */
-  void put(Source source, SourceEntry entry) {
-    entry.fixExceptionState();
-    _sourceMap[source] = entry;
-  }
-
-  /**
-   * Remove all information related to the given [source] from this partition.
-   * Return the entry associated with the source, or `null` if there was cache
-   * entry for the source.
-   */
-  SourceEntry remove(Source source) {
-    _recentlyUsed.remove(source);
-    return _sourceMap.remove(source);
-  }
-
-  /**
-   * Record that the AST associated with the given [source] was just removed
-   * from the cache.
-   */
-  void removedAst(Source source) {
-    _recentlyUsed.remove(source);
-  }
-
-  /**
-   * Return the number of sources that are mapped to cache entries.
-   */
-  int size() => _sourceMap.length;
-
-  /**
-   * Record that the AST associated with the given [source] was just stored to
-   * the cache.
-   */
-  void storedAst(Source source) {
-    if (_recentlyUsed.contains(source)) {
-      return;
-    }
-    while (_recentlyUsed.length >= _maxCacheSize) {
-      if (!_flushAstFromCache()) {
-        break;
-      }
-    }
-    _recentlyUsed.add(source);
-  }
-
-  /**
-   * Attempt to flush one AST structure from the cache. Return `true` if a
-   * structure was flushed.
-   */
-  bool _flushAstFromCache() {
-    Source removedSource = _removeAstToFlush();
-    if (removedSource == null) {
-      return false;
-    }
-    SourceEntry sourceEntry = _sourceMap[removedSource];
-    if (sourceEntry is HtmlEntry) {
-      HtmlEntry htmlEntry = sourceEntry;
-      htmlEntry.flushAstStructures();
-    } else if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      dartEntry.flushAstStructures();
-    }
-    return true;
-  }
-
-  /**
-   * Remove and return one source from the list of recently used sources whose
-   * AST structure can be flushed from the cache. The source that will be
-   * returned will be the source that has been unreferenced for the longest
-   * period of time but that is not a priority for analysis.
-   */
-  Source _removeAstToFlush() {
-    int sourceToRemove = -1;
-    for (int i = 0; i < _recentlyUsed.length; i++) {
-      Source source = _recentlyUsed[i];
-      RetentionPriority priority =
-          _retentionPolicy.getAstPriority(source, _sourceMap[source]);
-      if (priority == RetentionPriority.LOW) {
-        return _recentlyUsed.removeAt(i);
-      } else if (priority == RetentionPriority.MEDIUM && sourceToRemove < 0) {
-        sourceToRemove = i;
-      }
-    }
-    if (sourceToRemove < 0) {
-      // This happens if the retention policy returns a priority of HIGH for all
-      // of the sources that have been recently used. This is the case, for
-      // example, when the list of priority sources is bigger than the current
-      // cache size.
-      return null;
-    }
-    return _recentlyUsed.removeAt(sourceToRemove);
-  }
-}
-
-/**
- * An object used to determine how important it is for data to be retained in
- * the analysis cache.
- */
-abstract class CacheRetentionPolicy {
-  /**
-   * Return the priority of retaining the AST structure for the given [source].
-   */
-  RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry);
-}
-
-/**
  * The possible states of cached data.
  */
 class CacheState extends Enum<CacheState> {
   /**
    * The data is not in the cache and the last time an attempt was made to
    * compute the data an exception occurred, making it pointless to attempt to
    * compute the data again.
    *
    * Valid Transitions:
    * * [INVALID] if a source was modified that might cause the data to be
@@ skipping 429 matching lines @@
    */
   final V value;
 
   ComputedResult(this.context, this.descriptor, this.target, this.value);
 
   @override
   String toString() => '$descriptor of $target in $context';
 }
 
 /**
- * A pair containing a library and a list of the (source, entry) pairs for
- * compilation units in the library.
- */
-class CycleBuilder_LibraryPair {
-  /**
-   * The library containing the compilation units.
-   */
-  ResolvableLibrary library;
-
-  /**
-   * The (source, entry) pairs representing the compilation units in the
-   * library.
-   */
-  List<CycleBuilder_SourceEntryPair> entryPairs;
-
-  /**
-   * Initialize a newly created pair from the given [library] and [entryPairs].
-   */
-  CycleBuilder_LibraryPair(this.library, this.entryPairs);
-}
-
-/**
- * A pair containing a source and the cache entry associated with that source.
- * They are used to reduce the number of times an entry must be looked up in the
- * cache.
- */
-class CycleBuilder_SourceEntryPair {
-  /**
-   * The source associated with the entry.
-   */
-  Source source;
-
-  /**
-   * The entry associated with the source.
-   */
-  DartEntry entry;
-
-  /**
-   * Initialize a newly created pair from the given [source] and [entry].
-   */
-  CycleBuilder_SourceEntryPair(this.source, this.entry);
-}
-
-/**
- * The information cached by an analysis context about an individual Dart file.
- */
-class DartEntry extends SourceEntry {
-  /**
-   * The data descriptor representing the element model representing a single
-   * compilation unit. This model is incomplete and should not be used except as
-   * input to another task.
-   */
-  static final DataDescriptor<List<AnalysisError>> BUILT_ELEMENT =
-      new DataDescriptor<List<AnalysisError>>("DartEntry.BUILT_ELEMENT");
-
-  /**
-   * The data descriptor representing the AST structure after the element model
-   * has been built (and declarations are resolved) but before other resolution
-   * has been performed.
-   */
-  static final DataDescriptor<CompilationUnit> BUILT_UNIT =
-      new DataDescriptor<CompilationUnit>("DartEntry.BUILT_UNIT");
-
-  /**
-   * The data descriptor representing the list of libraries that contain this
-   * compilation unit.
-   */
-  static final DataDescriptor<List<Source>> CONTAINING_LIBRARIES =
-      new DataDescriptor<List<Source>>(
-          "DartEntry.CONTAINING_LIBRARIES", Source.EMPTY_LIST);
-
-  /**
-   * The data descriptor representing the library element for the library. This
-   * data is only available for Dart files that are the defining compilation
-   * unit of a library.
-   */
-  static final DataDescriptor<LibraryElement> ELEMENT =
-      new DataDescriptor<LibraryElement>("DartEntry.ELEMENT");
-
-  /**
-   * The data descriptor representing the list of exported libraries. This data
-   * is only available for Dart files that are the defining compilation unit of
-   * a library.
-   */
-  static final DataDescriptor<List<Source>> EXPORTED_LIBRARIES =
-      new DataDescriptor<List<Source>>(
-          "DartEntry.EXPORTED_LIBRARIES", Source.EMPTY_LIST);
-
-  /**
-   * The data descriptor representing the hints resulting from auditing the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> HINTS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.HINTS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the list of imported libraries. This data
-   * is only available for Dart files that are the defining compilation unit of
-   * a library.
-   */
-  static final DataDescriptor<List<Source>> IMPORTED_LIBRARIES =
-      new DataDescriptor<List<Source>>(
-          "DartEntry.IMPORTED_LIBRARIES", Source.EMPTY_LIST);
-
-  /**
-   * The data descriptor representing the list of included parts. This data is
-   * only available for Dart files that are the defining compilation unit of a
-   * library.
-   */
-  static final DataDescriptor<List<Source>> INCLUDED_PARTS =
-      new DataDescriptor<List<Source>>(
-          "DartEntry.INCLUDED_PARTS", Source.EMPTY_LIST);
-
-  /**
-   * The data descriptor representing the client flag. This data is only
-   * available for Dart files that are the defining compilation unit of a
-   * library.
-   */
-  static final DataDescriptor<bool> IS_CLIENT =
-      new DataDescriptor<bool>("DartEntry.IS_CLIENT", false);
-
-  /**
-   * The data descriptor representing the launchable flag. This data is only
-   * available for Dart files that are the defining compilation unit of a
-   * library.
-   */
-  static final DataDescriptor<bool> IS_LAUNCHABLE =
-      new DataDescriptor<bool>("DartEntry.IS_LAUNCHABLE", false);
-
-  /**
-   * The data descriptor representing lint warnings resulting from auditing the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> LINTS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.LINTS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the errors resulting from parsing the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> PARSE_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.PARSE_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the parsed AST structure.
-   */
-  static final DataDescriptor<CompilationUnit> PARSED_UNIT =
-      new DataDescriptor<CompilationUnit>("DartEntry.PARSED_UNIT");
-
-  /**
-   * The data descriptor representing the public namespace of the library. This
-   * data is only available for Dart files that are the defining compilation
-   * unit of a library.
-   */
-  static final DataDescriptor<Namespace> PUBLIC_NAMESPACE =
-      new DataDescriptor<Namespace>("DartEntry.PUBLIC_NAMESPACE");
-
-  /**
-   * The data descriptor representing the errors resulting from resolving the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> RESOLUTION_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.RESOLUTION_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the resolved AST structure.
-   */
-  static final DataDescriptor<CompilationUnit> RESOLVED_UNIT =
-      new DataDescriptor<CompilationUnit>("DartEntry.RESOLVED_UNIT");
-
-  /**
-   * The data descriptor representing the errors resulting from scanning the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> SCAN_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.SCAN_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the source kind.
-   */
-  static final DataDescriptor<SourceKind> SOURCE_KIND =
-      new DataDescriptor<SourceKind>(
-          "DartEntry.SOURCE_KIND", SourceKind.UNKNOWN);
-
-  /**
-   * The data descriptor representing the token stream.
-   */
-  static final DataDescriptor<Token> TOKEN_STREAM =
-      new DataDescriptor<Token>("DartEntry.TOKEN_STREAM");
-
-  /**
-   * The data descriptor representing the errors resulting from verifying the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> VERIFICATION_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "DartEntry.VERIFICATION_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The list of libraries that contain this compilation unit. The list will be
-   * empty if there are no known libraries that contain this compilation unit.
-   */
-  List<Source> _containingLibraries = new List<Source>();
-
-  /**
-   * The information known as a result of resolving this compilation unit as
-   * part of the library that contains this unit. This field will never be
-   * `null`.
-   */
-  ResolutionState _resolutionState = new ResolutionState();
-
-  /**
-   * Return all of the errors associated with the compilation unit that are
-   * currently cached.
-   */
-  List<AnalysisError> get allErrors {
-    List<AnalysisError> errors = new List<AnalysisError>();
-    errors.addAll(super.allErrors);
-    errors.addAll(getValue(SCAN_ERRORS));
-    errors.addAll(getValue(PARSE_ERRORS));
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      errors.addAll(state.getValue(RESOLUTION_ERRORS));
-      errors.addAll(state.getValue(VERIFICATION_ERRORS));
-      errors.addAll(state.getValue(HINTS));
-      errors.addAll(state.getValue(LINTS));
-      state = state._nextState;
-    }
-    if (errors.length == 0) {
-      return AnalysisError.NO_ERRORS;
-    }
-    return errors;
-  }
-
-  /**
-   * Return a valid parsed compilation unit, either an unresolved AST structure
-   * or the result of resolving the AST structure in the context of some
-   * library, or `null` if there is no parsed compilation unit available.
-   */
-  CompilationUnit get anyParsedCompilationUnit {
-    if (getState(PARSED_UNIT) == CacheState.VALID) {
-      return getValue(PARSED_UNIT);
-    }
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (state.getState(BUILT_UNIT) == CacheState.VALID) {
-        return state.getValue(BUILT_UNIT);
-      }
-      state = state._nextState;
-    }
-
-    return anyResolvedCompilationUnit;
-  }
-
-  /**
-   * Return the result of resolving the compilation unit as part of any library,
-   * or `null` if there is no cached resolved compilation unit.
-   */
-  CompilationUnit get anyResolvedCompilationUnit {
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (state.getState(RESOLVED_UNIT) == CacheState.VALID) {
-        return state.getValue(RESOLVED_UNIT);
-      }
-      state = state._nextState;
-    }
-    return null;
-  }
-
-  /**
-   * The libraries that are known to contain this part.
-   */
-  List<Source> get containingLibraries => _containingLibraries;
-
-  /**
-   * Set the list of libraries that contain this compilation unit to contain
-   * only the given [librarySource]. This method should only be invoked on
-   * entries that represent a library.
-   */
-  void set containingLibrary(Source librarySource) {
-    _containingLibraries.clear();
-    _containingLibraries.add(librarySource);
-  }
-
-  @override
-  List<DataDescriptor> get descriptors {
-    List<DataDescriptor> result = super.descriptors;
-    result.addAll(<DataDescriptor>[
-      DartEntry.SOURCE_KIND,
-      DartEntry.CONTAINING_LIBRARIES,
-      DartEntry.PARSE_ERRORS,
-      DartEntry.PARSED_UNIT,
-      DartEntry.SCAN_ERRORS,
-      DartEntry.SOURCE_KIND,
-      DartEntry.TOKEN_STREAM
-    ]);
-    SourceKind kind = getValue(DartEntry.SOURCE_KIND);
-    if (kind == SourceKind.LIBRARY) {
-      result.addAll(<DataDescriptor>[
-        DartEntry.ELEMENT,
-        DartEntry.EXPORTED_LIBRARIES,
-        DartEntry.IMPORTED_LIBRARIES,
-        DartEntry.INCLUDED_PARTS,
-        DartEntry.IS_CLIENT,
-        DartEntry.IS_LAUNCHABLE,
-        DartEntry.PUBLIC_NAMESPACE
-      ]);
-    }
-    return result;
-  }
-
-  /**
-   * Return `true` if this entry has an AST structure that can be resolved, even
-   * if it needs to be copied. Returning `true` implies that the method
-   * [resolvableCompilationUnit] will return a non-`null` result.
-   */
-  bool get hasResolvableCompilationUnit {
-    if (getState(PARSED_UNIT) == CacheState.VALID) {
-      return true;
-    }
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (state.getState(BUILT_UNIT) == CacheState.VALID ||
-          state.getState(RESOLVED_UNIT) == CacheState.VALID) {
-        return true;
-      }
-      state = state._nextState;
-    }
-
-    return false;
-  }
-
-  @override
-  SourceKind get kind => getValue(SOURCE_KIND);
-
-  /**
-   * The library sources containing the receiver's source.
-   */
-  List<Source> get librariesContaining {
-    ResolutionState state = _resolutionState;
-    List<Source> result = new List<Source>();
-    while (state != null) {
-      if (state._librarySource != null) {
-        result.add(state._librarySource);
-      }
-      state = state._nextState;
-    }
-    return result;
-  }
-
-  /**
-   * Get a list of all the library-dependent descriptors for which values may
-   * be stored in this SourceEntry.
-   */
-  List<DataDescriptor> get libraryDescriptors {
-    return <DataDescriptor>[
-      DartEntry.BUILT_ELEMENT,
-      DartEntry.BUILT_UNIT,
-      DartEntry.RESOLUTION_ERRORS,
-      DartEntry.RESOLVED_UNIT,
-      DartEntry.VERIFICATION_ERRORS,
-      DartEntry.HINTS,
-      DartEntry.LINTS
-    ];
-  }
-
-  /**
-   * A compilation unit that has not been accessed by any other client and can
-   * therefore safely be modified by the reconciler, or `null` if the source has
-   * not been parsed.
-   */
-  CompilationUnit get resolvableCompilationUnit {
-    if (getState(PARSED_UNIT) == CacheState.VALID) {
-      CompilationUnit unit = getValue(PARSED_UNIT);
-      setState(PARSED_UNIT, CacheState.FLUSHED);
-      return unit;
-    }
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (state.getState(BUILT_UNIT) == CacheState.VALID) {
-        // TODO(brianwilkerson) We're cloning the structure to remove any
-        // previous resolution data, but I'm not sure that's necessary.
-        return state.getValue(BUILT_UNIT).accept(new AstCloner());
-      }
-      if (state.getState(RESOLVED_UNIT) == CacheState.VALID) {
-        return state.getValue(RESOLVED_UNIT).accept(new AstCloner());
-      }
-      state = state._nextState;
-    }
-    return null;
-  }
-
-  /**
-   * Add the given [librarySource] to the list of libraries that contain this
-   * part. This method should only be invoked on entries that represent a part.
-   */
-  void addContainingLibrary(Source librarySource) {
-    _containingLibraries.add(librarySource);
-  }
-
-  /**
-   * Flush any AST structures being maintained by this entry.
-   */
-  void flushAstStructures() {
-    _flush(TOKEN_STREAM);
-    _flush(PARSED_UNIT);
-    _resolutionState.flushAstStructures();
-  }
-
-  /**
-   * Return the state of the data represented by the given [descriptor] in the
-   * context of the given [librarySource].
-   */
-  CacheState getStateInLibrary(
-      DataDescriptor descriptor, Source librarySource) {
-    if (!_isValidLibraryDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (librarySource == state._librarySource) {
-        return state.getState(descriptor);
-      }
-      state = state._nextState;
-    }
-    return CacheState.INVALID;
-  }
-
-  /**
-   * Return the value of the data represented by the given [descriptor] in the
-   * context of the given [librarySource], or `null` if the data represented by
-   * the descriptor is not in the cache.
-   */
-  Object getValueInLibrary(DataDescriptor descriptor, Source librarySource) {
-    if (!_isValidLibraryDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    ResolutionState state = _resolutionState;
-    while (state != null) {
-      if (librarySource == state._librarySource) {
-        return state.getValue(descriptor);
-      }
-      state = state._nextState;
-    }
-    return descriptor.defaultValue;
-  }
-
-  /**
-   * Return `true` if the data represented by the given [descriptor] is marked
-   * as being invalid. If the descriptor represents library-specific data then
-   * this method will return `true` if the data associated with any library it
-   * marked as invalid.
-   */
-  bool hasInvalidData(DataDescriptor descriptor) {
-    if (_isValidDescriptor(descriptor)) {
-      return getState(descriptor) == CacheState.INVALID;
-    } else if (_isValidLibraryDescriptor(descriptor)) {
-      ResolutionState state = _resolutionState;
-      while (state != null) {
-        if (state.getState(descriptor) == CacheState.INVALID) {
-          return true;
-        }
-        state = state._nextState;
-      }
-    }
-    return false;
-  }
-
-  @override
-  void invalidateAllInformation() {
-    super.invalidateAllInformation();
-    setState(SCAN_ERRORS, CacheState.INVALID);
-    setState(TOKEN_STREAM, CacheState.INVALID);
-    setState(SOURCE_KIND, CacheState.INVALID);
-    setState(PARSE_ERRORS, CacheState.INVALID);
-    setState(PARSED_UNIT, CacheState.INVALID);
-    _discardCachedResolutionInformation(true);
-  }
-
-  /**
-   * Invalidate all of the resolution information associated with the
-   * compilation unit. The flag [invalidateUris] should be `true` if the cached
-   * results of converting URIs to source files should also be invalidated.
-   */
-  void invalidateAllResolutionInformation(bool invalidateUris) {
-    if (getState(PARSED_UNIT) == CacheState.FLUSHED) {
-      ResolutionState state = _resolutionState;
-      while (state != null) {
-        if (state.getState(BUILT_UNIT) == CacheState.VALID) {
-          CompilationUnit unit = state.getValue(BUILT_UNIT);
-          setValue(PARSED_UNIT, unit.accept(new AstCloner()));
-          break;
-        } else if (state.getState(RESOLVED_UNIT) == CacheState.VALID) {
-          CompilationUnit unit = state.getValue(RESOLVED_UNIT);
-          setValue(PARSED_UNIT, unit.accept(new AstCloner()));
-          break;
-        }
-        state = state._nextState;
-      }
-    }
-    _discardCachedResolutionInformation(invalidateUris);
-  }
-
-  /**
-   * Invalidate all of the parse and resolution information associated with
-   * this source.
-   */
-  void invalidateParseInformation() {
-    setState(SOURCE_KIND, CacheState.INVALID);
-    setState(PARSE_ERRORS, CacheState.INVALID);
-    setState(PARSED_UNIT, CacheState.INVALID);
-    _containingLibraries.clear();
-    _discardCachedResolutionInformation(true);
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to build the element
-   * model for the source represented by this entry in the context of the given
-   * [library]. This will set the state of all resolution-based information as
-   * being in error, but will not change the state of any parse results.
-   */
-  void recordBuildElementErrorInLibrary(
-      Source librarySource, CaughtException exception) {
-    setStateInLibrary(BUILT_ELEMENT, librarySource, CacheState.ERROR);
-    setStateInLibrary(BUILT_UNIT, librarySource, CacheState.ERROR);
-    recordResolutionErrorInLibrary(librarySource, exception);
-  }
-
-  @override
-  void recordContentError(CaughtException exception) {
-    super.recordContentError(exception);
-    recordScanError(exception);
-  }
-
-  /**
-   * Record that an error occurred while attempting to generate hints for the
-   * source represented by this entry. This will set the state of all
-   * verification information as being in error. The [librarySource] is the
-   * source of the library in which hints were being generated. The [exception]
-   * is the exception that shows where the error occurred.
-   */
-  void recordHintErrorInLibrary(
-      Source librarySource, CaughtException exception) {
-    this.exception = exception;
-    ResolutionState state = _getOrCreateResolutionState(librarySource);
-    state.recordHintError();
-  }
-
-  /**
-   * Record that an error occurred while attempting to generate lints for the
-   * source represented by this entry. This will set the state of all
-   * verification information as being in error. The [librarySource] is the
-   * source of the library in which lints were being generated. The [exception]
-   * is the exception that shows where the error occurred.
-   */
-  void recordLintErrorInLibrary(
-      Source librarySource, CaughtException exception) {
-    this.exception = exception;
-    ResolutionState state = _getOrCreateResolutionState(librarySource);
-    state.recordLintError();
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to scan or parse the
-   * entry represented by this entry. This will set the state of all information,
-   * including any resolution-based information, as being in error.
-   */
-  void recordParseError(CaughtException exception) {
-    setState(SOURCE_KIND, CacheState.ERROR);
-    setState(PARSE_ERRORS, CacheState.ERROR);
-    setState(PARSED_UNIT, CacheState.ERROR);
-    setState(EXPORTED_LIBRARIES, CacheState.ERROR);
-    setState(IMPORTED_LIBRARIES, CacheState.ERROR);
-    setState(INCLUDED_PARTS, CacheState.ERROR);
-    recordResolutionError(exception);
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to resolve the source
-   * represented by this entry. This will set the state of all resolution-based
-   * information as being in error, but will not change the state of any parse
-   * results.
-   */
-  void recordResolutionError(CaughtException exception) {
-    this.exception = exception;
-    setState(ELEMENT, CacheState.ERROR);
-    setState(IS_CLIENT, CacheState.ERROR);
-    setState(IS_LAUNCHABLE, CacheState.ERROR);
-    setState(PUBLIC_NAMESPACE, CacheState.ERROR);
-    _resolutionState.recordResolutionErrorsInAllLibraries();
-  }
-
-  /**
-   * Record that an error occurred while attempting to resolve the source
-   * represented by this entry. This will set the state of all resolution-based
-   * information as being in error, but will not change the state of any parse
-   * results. The [librarySource] is the source of the library in which
-   * resolution was being performed. The [exception] is the exception that shows
-   * where the error occurred.
-   */
-  void recordResolutionErrorInLibrary(
-      Source librarySource, CaughtException exception) {
-    this.exception = exception;
-    setState(ELEMENT, CacheState.ERROR);
-    setState(IS_CLIENT, CacheState.ERROR);
-    setState(IS_LAUNCHABLE, CacheState.ERROR);
-    setState(PUBLIC_NAMESPACE, CacheState.ERROR);
-    ResolutionState state = _getOrCreateResolutionState(librarySource);
-    state.recordResolutionError();
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to scan or parse the
-   * entry represented by this entry. This will set the state of all
-   * information, including any resolution-based information, as being in error.
-   */
-  @override
-  void recordScanError(CaughtException exception) {
-    super.recordScanError(exception);
-    setState(SCAN_ERRORS, CacheState.ERROR);
-    setState(TOKEN_STREAM, CacheState.ERROR);
-    recordParseError(exception);
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to generate errors and
-   * warnings for the source represented by this entry. This will set the state
-   * of all verification information as being in error. The [librarySource] is
-   * the source of the library in which verification was being performed. The
-   * [exception] is the exception that shows where the error occurred.
-   */
-  void recordVerificationErrorInLibrary(
-      Source librarySource, CaughtException exception) {
-    this.exception = exception;
-    ResolutionState state = _getOrCreateResolutionState(librarySource);
-    state.recordVerificationError();
-  }
-
-  /**
-   * Remove the given [library] from the list of libraries that contain this
-   * part. This method should only be invoked on entries that represent a part.
-   */
-  void removeContainingLibrary(Source library) {
-    _containingLibraries.remove(library);
-  }
-
-  /**
-   * Remove any resolution information associated with this compilation unit
-   * being part of the given [library], presumably because it is no longer part
-   * of the library.
-   */
-  void removeResolution(Source library) {
-    if (library != null) {
-      if (library == _resolutionState._librarySource) {
-        if (_resolutionState._nextState == null) {
-          _resolutionState.invalidateAllResolutionInformation();
-        } else {
-          _resolutionState = _resolutionState._nextState;
-        }
-      } else {
-        ResolutionState priorState = _resolutionState;
-        ResolutionState state = _resolutionState._nextState;
-        while (state != null) {
-          if (library == state._librarySource) {
-            priorState._nextState = state._nextState;
-            break;
-          }
-          priorState = state;
-          state = state._nextState;
-        }
-      }
-    }
-  }
-
-  /**
-   * Set the state of the data represented by the given [descriptor] in the
-   * context of the given [library] to the given [state].
-   */
-  void setStateInLibrary(
-      DataDescriptor descriptor, Source library, CacheState state) {
-    if (!_isValidLibraryDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    ResolutionState resolutionState = _getOrCreateResolutionState(library);
-    resolutionState.setState(descriptor, state);
-  }
-
-  /**
-   * Set the value of the data represented by the given [descriptor] in the
-   * context of the given [library] to the given [value], and set the state of
-   * that data to [CacheState.VALID].
-   */
-  void setValueInLibrary(
-      DataDescriptor descriptor, Source library, Object value) {
-    if (!_isValidLibraryDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    ResolutionState state = _getOrCreateResolutionState(library);
-    state.setValue(descriptor, value);
-  }
-
-  /**
-   * Invalidate all of the resolution information associated with the
-   * compilation unit. The flag [invalidateUris] should be `true` if the cached
-   * results of converting URIs to source files should also be invalidated.
-   */
-  void _discardCachedResolutionInformation(bool invalidateUris) {
-    setState(ELEMENT, CacheState.INVALID);
-    setState(IS_CLIENT, CacheState.INVALID);
-    setState(IS_LAUNCHABLE, CacheState.INVALID);
-    setState(PUBLIC_NAMESPACE, CacheState.INVALID);
-    _resolutionState.invalidateAllResolutionInformation();
-    if (invalidateUris) {
-      setState(EXPORTED_LIBRARIES, CacheState.INVALID);
-      setState(IMPORTED_LIBRARIES, CacheState.INVALID);
-      setState(INCLUDED_PARTS, CacheState.INVALID);
-    }
-  }
-
-  /**
-   * Return a resolution state for the specified [library], creating one as
-   * necessary.
-   */
-  ResolutionState _getOrCreateResolutionState(Source library) {
-    ResolutionState state = _resolutionState;
-    if (state._librarySource == null) {
-      state._librarySource = library;
-      return state;
-    }
-    while (state._librarySource != library) {
-      if (state._nextState == null) {
-        ResolutionState newState = new ResolutionState();
-        newState._librarySource = library;
-        state._nextState = newState;
-        return newState;
-      }
-      state = state._nextState;
-    }
-    return state;
-  }
-
-  @override
-  bool _isValidDescriptor(DataDescriptor descriptor) {
-    return descriptor == CONTAINING_LIBRARIES ||
-        descriptor == ELEMENT ||
-        descriptor == EXPORTED_LIBRARIES ||
-        descriptor == IMPORTED_LIBRARIES ||
-        descriptor == INCLUDED_PARTS ||
-        descriptor == IS_CLIENT ||
-        descriptor == IS_LAUNCHABLE ||
-        descriptor == PARSED_UNIT ||
-        descriptor == PARSE_ERRORS ||
-        descriptor == PUBLIC_NAMESPACE ||
-        descriptor == SCAN_ERRORS ||
-        descriptor == SOURCE_KIND ||
-        descriptor == TOKEN_STREAM ||
-        super._isValidDescriptor(descriptor);
-  }
-
-  /**
-   * Return `true` if the [descriptor] is valid for this entry when the data is
-   * relative to a library.
-   */
-  bool _isValidLibraryDescriptor(DataDescriptor descriptor) {
-    return descriptor == BUILT_ELEMENT ||
-        descriptor == BUILT_UNIT ||
-        descriptor == HINTS ||
-        descriptor == LINTS ||
-        descriptor == RESOLUTION_ERRORS ||
-        descriptor == RESOLVED_UNIT ||
-        descriptor == VERIFICATION_ERRORS;
-  }
-
-  @override
-  bool _writeDiffOn(StringBuffer buffer, SourceEntry oldEntry) {
-    bool needsSeparator = super._writeDiffOn(buffer, oldEntry);
-    if (oldEntry is! DartEntry) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write("entry type changed; was ");
-      buffer.write(oldEntry.runtimeType.toString());
-      return true;
-    }
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "tokenStream",
-        DartEntry.TOKEN_STREAM, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "scanErrors", DartEntry.SCAN_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "sourceKind", DartEntry.SOURCE_KIND, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "parsedUnit", DartEntry.PARSED_UNIT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "parseErrors",
-        DartEntry.PARSE_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "importedLibraries", DartEntry.IMPORTED_LIBRARIES, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "exportedLibraries", DartEntry.EXPORTED_LIBRARIES, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "includedParts",
-        DartEntry.INCLUDED_PARTS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "element", DartEntry.ELEMENT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "publicNamespace", DartEntry.PUBLIC_NAMESPACE, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "clientServer", DartEntry.IS_CLIENT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "launchable",
-        DartEntry.IS_LAUNCHABLE, oldEntry);
-    // TODO(brianwilkerson) Add better support for containingLibraries.
-    // It would be nice to be able to report on size-preserving changes.
-    int oldLibraryCount = (oldEntry as DartEntry)._containingLibraries.length;
-    int libraryCount = _containingLibraries.length;
-    if (oldLibraryCount != libraryCount) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write("containingLibraryCount = ");
-      buffer.write(oldLibraryCount);
-      buffer.write(" -> ");
-      buffer.write(libraryCount);
-      needsSeparator = true;
-    }
-    //
-    // Report change to the per-library state.
-    //
-    HashMap<Source, ResolutionState> oldStateMap =
-        new HashMap<Source, ResolutionState>();
-    ResolutionState state = (oldEntry as DartEntry)._resolutionState;
-    while (state != null) {
-      Source librarySource = state._librarySource;
-      if (librarySource != null) {
-        oldStateMap[librarySource] = state;
-      }
-      state = state._nextState;
-    }
-    state = _resolutionState;
-    while (state != null) {
-      Source librarySource = state._librarySource;
-      if (librarySource != null) {
-        ResolutionState oldState = oldStateMap.remove(librarySource);
-        if (oldState == null) {
-          if (needsSeparator) {
-            buffer.write("; ");
-          }
-          buffer.write("added resolution for ");
-          buffer.write(librarySource.fullName);
-          needsSeparator = true;
-        } else {
-          needsSeparator = oldState._writeDiffOn(
-              buffer, needsSeparator, oldEntry as DartEntry);
-        }
-      }
-      state = state._nextState;
-    }
-    for (Source librarySource in oldStateMap.keys.toSet()) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write("removed resolution for ");
-      buffer.write(librarySource.fullName);
-      needsSeparator = true;
-    }
-    return needsSeparator;
-  }
-
-  @override
-  void _writeOn(StringBuffer buffer) {
-    buffer.write("Dart: ");
-    super._writeOn(buffer);
-    _writeStateOn(buffer, "tokenStream", TOKEN_STREAM);
-    _writeStateOn(buffer, "scanErrors", SCAN_ERRORS);
-    _writeStateOn(buffer, "sourceKind", SOURCE_KIND);
-    _writeStateOn(buffer, "parsedUnit", PARSED_UNIT);
-    _writeStateOn(buffer, "parseErrors", PARSE_ERRORS);
-    _writeStateOn(buffer, "exportedLibraries", EXPORTED_LIBRARIES);
-    _writeStateOn(buffer, "importedLibraries", IMPORTED_LIBRARIES);
-    _writeStateOn(buffer, "includedParts", INCLUDED_PARTS);
-    _writeStateOn(buffer, "element", ELEMENT);
-    _writeStateOn(buffer, "publicNamespace", PUBLIC_NAMESPACE);
-    _writeStateOn(buffer, "clientServer", IS_CLIENT);
-    _writeStateOn(buffer, "launchable", IS_LAUNCHABLE);
-    _resolutionState._writeOn(buffer);
-  }
-}
-
-/**
- * An immutable constant representing data that can be stored in the cache.
- */
-class DataDescriptor<E> {
-  /**
-   * The next artificial hash code.
-   */
-  static int _NEXT_HASH_CODE = 0;
-
-  /**
-   * The artifitial hash code for this object.
-   */
-  final int _hashCode = _NEXT_HASH_CODE++;
-
-  /**
-   * The name of the descriptor, used for debugging purposes.
-   */
-  final String _name;
-
-  /**
-   * The default value used when the data does not exist.
-   */
-  final E defaultValue;
-
-  /**
-   * Initialize a newly created descriptor to have the given [name] and
-   * [defaultValue].
-   */
-  DataDescriptor(this._name, [this.defaultValue = null]);
-
-  @override
-  int get hashCode => _hashCode;
-
-  @override
-  String toString() => _name;
-}
-
-/**
- * A retention policy that will keep AST's in the cache if there is analysis
- * information that needs to be computed for a source, where the computation is
- * dependent on having the AST.
- */
-class DefaultRetentionPolicy implements CacheRetentionPolicy {
-  /**
-   * An instance of this class that can be shared.
-   */
-  static DefaultRetentionPolicy POLICY = new DefaultRetentionPolicy();
-
-  /**
-   * Return `true` if there is analysis information in the given [dartEntry]
-   * that needs to be computed, where the computation is dependent on having the
-   * AST.
-   */
-  bool astIsNeeded(DartEntry dartEntry) =>
-      dartEntry.hasInvalidData(DartEntry.HINTS) ||
-          dartEntry.hasInvalidData(DartEntry.LINTS) ||
-          dartEntry.hasInvalidData(DartEntry.VERIFICATION_ERRORS) ||
-          dartEntry.hasInvalidData(DartEntry.RESOLUTION_ERRORS);
-
-  @override
-  RetentionPriority getAstPriority(Source source, SourceEntry sourceEntry) {
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      if (astIsNeeded(dartEntry)) {
-        return RetentionPriority.MEDIUM;
-      }
-    }
-    return RetentionPriority.LOW;
-  }
-}
-
-/**
- * Instances of the class `GenerateDartErrorsTask` generate errors and warnings for a single
- * Dart source.
- */
-class GenerateDartErrorsTask extends AnalysisTask {
-  /**
-   * The source for which errors and warnings are to be produced.
-   */
-  final Source source;
-
-  /**
-   * The compilation unit used to resolve the dependencies.
-   */
-  final CompilationUnit _unit;
-
-  /**
-   * The element model for the library containing the source.
-   */
-  final LibraryElement libraryElement;
-
-  /**
-   * The errors that were generated for the source.
-   */
-  List<AnalysisError> _errors;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source for which errors and warnings are to be produced
-   * @param unit the compilation unit used to resolve the dependencies
-   * @param libraryElement the element model for the library containing the source
-   */
-  GenerateDartErrorsTask(InternalAnalysisContext context, this.source,
-      this._unit, this.libraryElement)
-      : super(context);
-
-  /**
-   * Return the errors that were generated for the source.
-   *
-   * @return the errors that were generated for the source
-   */
-  List<AnalysisError> get errors => _errors;
-
-  @override
-  String get taskDescription =>
-      "generate errors and warnings for ${source.fullName}";
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitGenerateDartErrorsTask(this);
-
-  @override
-  void internalPerform() {
-    PerformanceStatistics.errors.makeCurrentWhile(() {
-      RecordingErrorListener errorListener = new RecordingErrorListener();
-      ErrorReporter errorReporter = new ErrorReporter(errorListener, source);
-      TypeProvider typeProvider = context.typeProvider;
-      //
-      // Validate the directives
-      //
-      validateDirectives(context, source, _unit, errorListener);
-      //
-      // Use the ConstantVerifier to verify the use of constants.
-      // This needs to happen before using the ErrorVerifier because some error
-      // codes need the computed constant values.
-      //
-      // TODO(paulberry): as a temporary workaround for issue 21572,
-      // ConstantVerifier is being run right after ConstantValueComputer, so we
-      // don't need to run it here.  Once issue 21572 is fixed, re-enable the
-      // call to ConstantVerifier.
-//      ConstantVerifier constantVerifier = new ConstantVerifier(errorReporter, libraryElement, typeProvider);
-//      _unit.accept(constantVerifier);
-      //
-      // Use the ErrorVerifier to compute the rest of the errors.
-      //
-      ErrorVerifier errorVerifier = new ErrorVerifier(
-          errorReporter,
-          libraryElement,
-          typeProvider,
-          new InheritanceManager(libraryElement),
-          context.analysisOptions.enableSuperMixins,
-          context.analysisOptions.enableAssertMessage);
-      _unit.accept(errorVerifier);
-      _errors = errorListener.getErrorsForSource(source);
-    });
-  }
-
-  /**
-   * Check each directive in the given compilation unit to see if the referenced source exists and
-   * report an error if it does not.
-   *
-   * @param context the context in which the library exists
-   * @param librarySource the source representing the library containing the directives
-   * @param unit the compilation unit containing the directives to be validated
-   * @param errorListener the error listener to which errors should be reported
-   */
-  static void validateDirectives(AnalysisContext context, Source librarySource,
-      CompilationUnit unit, AnalysisErrorListener errorListener) {
-    for (Directive directive in unit.directives) {
-      if (directive is UriBasedDirective) {
-        validateReferencedSource(
-            context, librarySource, directive, errorListener);
-      }
-    }
-  }
-
-  /**
-   * Check the given directive to see if the referenced source exists and report an error if it does
-   * not.
-   *
-   * @param context the context in which the library exists
-   * @param librarySource the source representing the library containing the directive
-   * @param directive the directive to be verified
-   * @param errorListener the error listener to which errors should be reported
-   */
-  static void validateReferencedSource(
-      AnalysisContext context,
-      Source librarySource,
-      UriBasedDirective directive,
-      AnalysisErrorListener errorListener) {
-    Source source = directive.source;
-    if (source != null) {
-      if (context.exists(source)) {
-        return;
-      }
-    } else {
-      // Don't report errors already reported by ParseDartTask.resolveDirective
-      if (directive.validate() != null) {
-        return;
-      }
-    }
-    StringLiteral uriLiteral = directive.uri;
-    errorListener.onError(new AnalysisError(
-        librarySource,
-        uriLiteral.offset,
-        uriLiteral.length,
-        CompileTimeErrorCode.URI_DOES_NOT_EXIST,
-        [directive.uriContent]));
-  }
-}
-
-/**
- * Instances of the class `GenerateDartHintsTask` generate hints for a single Dart library.
- */
-class GenerateDartHintsTask extends AnalysisTask {
-  /**
-   * The compilation units that comprise the library, with the defining compilation unit appearing
-   * first in the list.
-   */
-  final List<TimestampedData<CompilationUnit>> _units;
-
-  /**
-   * The element model for the library being analyzed.
-   */
-  final LibraryElement libraryElement;
-
-  /**
-   * A table mapping the sources that were analyzed to the hints that were
-   * generated for the sources.
-   */
-  HashMap<Source, List<AnalysisError>> _hintMap;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param units the compilation units that comprise the library, with the defining compilation
-   *          unit appearing first in the list
-   * @param libraryElement the element model for the library being analyzed
-   */
-  GenerateDartHintsTask(
-      InternalAnalysisContext context, this._units, this.libraryElement)
-      : super(context);
-
-  /**
-   * Return a table mapping the sources that were analyzed to the hints that were generated for the
-   * sources, or `null` if the task has not been performed or if the analysis did not complete
-   * normally.
-   *
-   * @return a table mapping the sources that were analyzed to the hints that were generated for the
-   *         sources
-   */
-  HashMap<Source, List<AnalysisError>> get hintMap => _hintMap;
-
-  @override
-  String get taskDescription {
-    Source librarySource = libraryElement.source;
-    if (librarySource == null) {
-      return "generate Dart hints for library without source";
-    }
-    return "generate Dart hints for ${librarySource.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitGenerateDartHintsTask(this);
-
-  @override
-  void internalPerform() {
-    //
-    // Gather the compilation units.
-    //
-    int unitCount = _units.length;
-    List<CompilationUnit> compilationUnits =
-        new List<CompilationUnit>(unitCount);
-    for (int i = 0; i < unitCount; i++) {
-      compilationUnits[i] = _units[i].data;
-    }
-    //
-    // Analyze all of the units.
-    //
-    RecordingErrorListener errorListener = new RecordingErrorListener();
-    HintGenerator hintGenerator =
-        new HintGenerator(compilationUnits, context, errorListener);
-    hintGenerator.generateForLibrary();
-    //
-    // Store the results.
-    //
-    _hintMap = new HashMap<Source, List<AnalysisError>>();
-    for (int i = 0; i < unitCount; i++) {
-      Source source = _units[i].data.element.source;
-      _hintMap[source] = errorListener.getErrorsForSource(source);
-    }
-  }
-}
-
-/// Generates lint feedback for a single Dart library.
-class GenerateDartLintsTask extends AnalysisTask {
-  ///The compilation units that comprise the library, with the defining
-  ///compilation unit appearing first in the list.
-  final List<TimestampedData<CompilationUnit>> _units;
-
-  /// The element model for the library being analyzed.
-  final LibraryElement libraryElement;
-
-  /// A mapping of analyzed sources to their associated lint warnings.
-  /// May be [null] if the task has not been performed or if analysis did not
-  /// complete normally.
-  HashMap<Source, List<AnalysisError>> lintMap;
-
-  /// Initialize a newly created task to perform lint checking over these
-  /// [_units] belonging to this [libraryElement] within the given [context].
-  GenerateDartLintsTask(context, this._units, this.libraryElement)
-      : super(context);
-
-  @override
-  String get taskDescription {
-    Source librarySource = libraryElement.source;
-    return (librarySource == null)
-        ? "generate Dart lints for library without source"
-        : "generate Dart lints for ${librarySource.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitGenerateDartLintsTask(this);
-
-  @override
-  void internalPerform() {
-    Iterable<CompilationUnit> compilationUnits =
-        _units.map((TimestampedData<CompilationUnit> unit) => unit.data);
-    RecordingErrorListener errorListener = new RecordingErrorListener();
-    LintGenerator lintGenerator =
-        new LintGenerator(compilationUnits, errorListener);
-    lintGenerator.generate();
-
-    lintMap = new HashMap<Source, List<AnalysisError>>();
-    compilationUnits.forEach((CompilationUnit unit) {
-      Source source = unit.element.source;
-      lintMap[source] = errorListener.getErrorsForSource(source);
-    });
-  }
-}
-
-/**
- * Instances of the class `GetContentTask` get the contents of a source.
- */
-class GetContentTask extends AnalysisTask {
-  /**
-   * The source to be read.
-   */
-  final Source source;
-
-  /**
-   * A flag indicating whether this task is complete.
-   */
-  bool _complete = false;
-
-  /**
-   * The contents of the source.
-   */
-  String _content;
-
-  /**
-   * The errors that were produced by getting the source content.
-   */
-  final List<AnalysisError> errors = <AnalysisError>[];
-
-  /**
-   * The time at which the contents of the source were last modified.
-   */
-  int _modificationTime = -1;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be parsed
-   * @param contentData the time-stamped contents of the source
-   */
-  GetContentTask(InternalAnalysisContext context, this.source)
-      : super(context) {
-    if (source == null) {
-      throw new IllegalArgumentException("Cannot get contents of null source");
-    }
-  }
-
-  /**
-   * Return the contents of the source, or `null` if the task has not completed or if there
-   * was an exception while getting the contents.
-   *
-   * @return the contents of the source
-   */
-  String get content => _content;
-
-  /**
-   * Return `true` if this task is complete. Unlike most tasks, this task is allowed to be
-   * visited more than once in order to support asynchronous IO. If the task is not complete when it
-   * is visited synchronously as part of the [AnalysisTask.perform]
-   * method, it will be visited again, using the same visitor, when the IO operation has been
-   * performed.
-   *
-   * @return `true` if this task is complete
-   */
-  bool get isComplete => _complete;
-
-  /**
-   * Return the time at which the contents of the source that was parsed were last modified, or a
-   * negative value if the task has not yet been performed or if an exception occurred.
-   *
-   * @return the time at which the contents of the source that was parsed were last modified
-   */
-  int get modificationTime => _modificationTime;
-
-  @override
-  String get taskDescription => "get contents of ${source.fullName}";
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitGetContentTask(this);
-
-  @override
-  void internalPerform() {
-    _complete = true;
-    try {
-      TimestampedData<String> data = context.getContents(source);
-      _content = data.data;
-      _modificationTime = data.modificationTime;
-      AnalysisEngine.instance.instrumentationService
-          .logFileRead(source.fullName, _modificationTime, _content);
-    } catch (exception, stackTrace) {
-      if (source.exists()) {
-        errors.add(new AnalysisError(
-            source, 0, 0, ScannerErrorCode.UNABLE_GET_CONTENT, [exception]));
-      }
-      throw new AnalysisException("Could not get contents of $source",
-          new CaughtException(exception, stackTrace));
-    }
-  }
-}
-
-/**
- * The information cached by an analysis context about an individual HTML file.
- */
-class HtmlEntry extends SourceEntry {
-  /**
-   * The data descriptor representing the HTML element.
-   */
-  static final DataDescriptor<HtmlElement> ELEMENT =
-      new DataDescriptor<HtmlElement>("HtmlEntry.ELEMENT");
-
-  /**
-   * The data descriptor representing the hints resulting from auditing the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> HINTS =
-      new DataDescriptor<List<AnalysisError>>(
-          "HtmlEntry.HINTS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the errors resulting from parsing the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> PARSE_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "HtmlEntry.PARSE_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the parsed AST structure.
-   */
-  static final DataDescriptor<ht.HtmlUnit> PARSED_UNIT =
-      new DataDescriptor<ht.HtmlUnit>("HtmlEntry.PARSED_UNIT");
-
-  /**
-   * The data descriptor representing the resolved AST structure.
-   */
-  static final DataDescriptor<ht.HtmlUnit> RESOLVED_UNIT =
-      new DataDescriptor<ht.HtmlUnit>("HtmlEntry.RESOLVED_UNIT");
-
-  /**
-   * The data descriptor representing the list of referenced libraries.
-   */
-  static final DataDescriptor<List<Source>> REFERENCED_LIBRARIES =
-      new DataDescriptor<List<Source>>(
-          "HtmlEntry.REFERENCED_LIBRARIES", Source.EMPTY_LIST);
-
-  /**
-   * The data descriptor representing the errors resulting from resolving the
-   * source.
-   */
-  static final DataDescriptor<List<AnalysisError>> RESOLUTION_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "HtmlEntry.RESOLUTION_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * Return all of the errors associated with the HTML file that are currently
-   * cached.
-   */
-  List<AnalysisError> get allErrors {
-    List<AnalysisError> errors = new List<AnalysisError>();
-    errors.addAll(super.allErrors);
-    errors.addAll(getValue(PARSE_ERRORS));
-    errors.addAll(getValue(RESOLUTION_ERRORS));
-    errors.addAll(getValue(HINTS));
-    if (errors.length == 0) {
-      return AnalysisError.NO_ERRORS;
-    }
-    return errors;
-  }
-
-  /**
-   * Return a valid parsed unit, either an unresolved AST structure or the
-   * result of resolving the AST structure, or `null` if there is no parsed unit
-   * available.
-   */
-  ht.HtmlUnit get anyParsedUnit {
-    if (getState(PARSED_UNIT) == CacheState.VALID) {
-      return getValue(PARSED_UNIT);
-    }
-    if (getState(RESOLVED_UNIT) == CacheState.VALID) {
-      return getValue(RESOLVED_UNIT);
-    }
-    return null;
-  }
-
-  @override
-  List<DataDescriptor> get descriptors {
-    List<DataDescriptor> result = super.descriptors;
-    result.addAll([
-      HtmlEntry.ELEMENT,
-      HtmlEntry.PARSE_ERRORS,
-      HtmlEntry.PARSED_UNIT,
-      HtmlEntry.RESOLUTION_ERRORS,
-      HtmlEntry.RESOLVED_UNIT,
-      HtmlEntry.HINTS
-    ]);
-    return result;
-  }
-
-  @override
-  SourceKind get kind => SourceKind.HTML;
-
-  /**
-   * Flush any AST structures being maintained by this entry.
-   */
-  void flushAstStructures() {
-    _flush(PARSED_UNIT);
-    _flush(RESOLVED_UNIT);
-  }
-
-  @override
-  void invalidateAllInformation() {
-    super.invalidateAllInformation();
-    setState(PARSE_ERRORS, CacheState.INVALID);
-    setState(PARSED_UNIT, CacheState.INVALID);
-    setState(RESOLVED_UNIT, CacheState.INVALID);
-    invalidateAllResolutionInformation(true);
-  }
-
-  /**
-   * Invalidate all of the resolution information associated with the HTML file.
-   * If [invalidateUris] is `true`, the cached results of converting URIs to
-   * source files should also be invalidated.
-   */
-  void invalidateAllResolutionInformation(bool invalidateUris) {
-    setState(RESOLVED_UNIT, CacheState.INVALID);
-    setState(ELEMENT, CacheState.INVALID);
-    setState(RESOLUTION_ERRORS, CacheState.INVALID);
-    setState(HINTS, CacheState.INVALID);
-    if (invalidateUris) {
-      setState(REFERENCED_LIBRARIES, CacheState.INVALID);
-    }
-  }
-
-  /**
-   * Invalidate all of the parse and resolution information associated with
-   * this source.
-   */
-  void invalidateParseInformation() {
-    setState(PARSE_ERRORS, CacheState.INVALID);
-    setState(PARSED_UNIT, CacheState.INVALID);
-    invalidateAllResolutionInformation(true);
-  }
-
-  @override
-  void recordContentError(CaughtException exception) {
-    super.recordContentError(exception);
-    recordParseError(exception);
-  }
-
-  /**
-   * Record that an [exception] was encountered while attempting to parse the
-   * source associated with this entry.
-   */
-  void recordParseError(CaughtException exception) {
-    // If the scanning and parsing of HTML are separated,
-    // the following line can be removed.
-    recordScanError(exception);
-    setState(PARSE_ERRORS, CacheState.ERROR);
-    setState(PARSED_UNIT, CacheState.ERROR);
-    setState(REFERENCED_LIBRARIES, CacheState.ERROR);
-    recordResolutionError(exception);
-  }
-
-  /**
-   * Record that an [exception] was encountered while attempting to resolve the
-   * source associated with this entry.
-   */
-  void recordResolutionError(CaughtException exception) {
-    this.exception = exception;
-    setState(RESOLVED_UNIT, CacheState.ERROR);
-    setState(ELEMENT, CacheState.ERROR);
-    setState(RESOLUTION_ERRORS, CacheState.ERROR);
-    setState(HINTS, CacheState.ERROR);
-  }
-
-  @override
-  bool _isValidDescriptor(DataDescriptor descriptor) {
-    return descriptor == ELEMENT ||
-        descriptor == HINTS ||
-        descriptor == PARSED_UNIT ||
-        descriptor == PARSE_ERRORS ||
-        descriptor == REFERENCED_LIBRARIES ||
-        descriptor == RESOLUTION_ERRORS ||
-        descriptor == RESOLVED_UNIT ||
-        super._isValidDescriptor(descriptor);
-  }
-
-  @override
-  bool _writeDiffOn(StringBuffer buffer, SourceEntry oldEntry) {
-    bool needsSeparator = super._writeDiffOn(buffer, oldEntry);
-    if (oldEntry is! HtmlEntry) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write("entry type changed; was ");
-      buffer.write(oldEntry.runtimeType);
-      return true;
-    }
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "parseErrors",
-        HtmlEntry.PARSE_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "parsedUnit", HtmlEntry.PARSED_UNIT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "resolvedUnit",
-        HtmlEntry.RESOLVED_UNIT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "resolutionErrors", HtmlEntry.RESOLUTION_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "referencedLibraries", HtmlEntry.REFERENCED_LIBRARIES, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "element", HtmlEntry.ELEMENT, oldEntry);
-    return needsSeparator;
-  }
-
-  @override
-  void _writeOn(StringBuffer buffer) {
-    buffer.write("Html: ");
-    super._writeOn(buffer);
-    _writeStateOn(buffer, "parseErrors", PARSE_ERRORS);
-    _writeStateOn(buffer, "parsedUnit", PARSED_UNIT);
-    _writeStateOn(buffer, "resolvedUnit", RESOLVED_UNIT);
-    _writeStateOn(buffer, "resolutionErrors", RESOLUTION_ERRORS);
-    _writeStateOn(buffer, "referencedLibraries", REFERENCED_LIBRARIES);
-    _writeStateOn(buffer, "element", ELEMENT);
-  }
-}
-
-/**
  * An event indicating when a source either starts or stops being implicitly
  * analyzed.
  */
 class ImplicitAnalysisEvent {
   /**
    * The source whose status has changed.
    */
   final Source source;
 
   /**
    * A flag indicating whether the source is now being analyzed.
    */
   final bool isAnalyzed;
 
   /**
    * Initialize a newly created event to indicate that the given [source] has
    * changed it status to match the [isAnalyzed] flag.
    */
   ImplicitAnalysisEvent(this.source, this.isAnalyzed);
 
   @override
   String toString() =>
       '${isAnalyzed ? '' : 'not '}analyzing ${source.fullName}';
 }
 
 /**
- * Instances of the class `IncrementalAnalysisCache` hold information used to perform
- * incremental analysis.
- *
- * See [AnalysisContextImpl.setChangedContents].
- */
-class IncrementalAnalysisCache {
-  final Source librarySource;
-
-  final Source source;
-
-  final String oldContents;
-
-  final CompilationUnit resolvedUnit;
-
-  String _newContents;
-
-  int _offset = 0;
-
-  int _oldLength = 0;
-
-  int _newLength = 0;
-
-  IncrementalAnalysisCache(
-      this.librarySource,
-      this.source,
-      this.resolvedUnit,
-      this.oldContents,
-      this._newContents,
-      this._offset,
-      this._oldLength,
-      this._newLength);
-
-  /**
-   * Determine if the cache contains source changes that need to be analyzed
-   *
-   * @return `true` if the cache contains changes to be analyzed, else `false`
-   */
-  bool get hasWork => _oldLength > 0 || _newLength > 0;
-
-  /**
-   * Return the current contents for the receiver's source.
-   *
-   * @return the contents (not `null`)
-   */
-  String get newContents => _newContents;
-
-  /**
-   * Return the number of characters in the replacement text.
-   *
-   * @return the replacement length (zero or greater)
-   */
-  int get newLength => _newLength;
-
-  /**
-   * Return the character position of the first changed character.
-   *
-   * @return the offset (zero or greater)
-   */
-  int get offset => _offset;
-
-  /**
-   * Return the number of characters that were replaced.
-   *
-   * @return the replaced length (zero or greater)
-   */
-  int get oldLength => _oldLength;
-
-  /**
-   * Determine if the incremental analysis result can be cached for the next incremental analysis.
-   *
-   * @param cache the prior incremental analysis cache
-   * @param unit the incrementally updated compilation unit
-   * @return the cache used for incremental analysis or `null` if incremental analysis results
-   *         cannot be cached for the next incremental analysis
-   */
-  static IncrementalAnalysisCache cacheResult(
-      IncrementalAnalysisCache cache, CompilationUnit unit) {
-    if (cache != null && unit != null) {
-      return new IncrementalAnalysisCache(cache.librarySource, cache.source,
-          unit, cache._newContents, cache._newContents, 0, 0, 0);
-    }
-    return null;
-  }
-
-  /**
-   * Determine if the cache should be cleared.
-   *
-   * @param cache the prior cache or `null` if none
-   * @param source the source being updated (not `null`)
-   * @return the cache used for incremental analysis or `null` if incremental analysis cannot
-   *         be performed
-   */
-  static IncrementalAnalysisCache clear(
-      IncrementalAnalysisCache cache, Source source) {
-    if (cache == null || cache.source == source) {
-      return null;
-    }
-    return cache;
-  }
-
-  /**
-   * Determine if incremental analysis can be performed from the given information.
-   *
-   * @param cache the prior cache or `null` if none
-   * @param source the source being updated (not `null`)
-   * @param oldContents the original source contents prior to this update (may be `null`)
-   * @param newContents the new contents after this incremental change (not `null`)
-   * @param offset the offset at which the change occurred
-   * @param oldLength the length of the text being replaced
-   * @param newLength the length of the replacement text
-   * @param sourceEntry the cached entry for the given source or `null` if none
-   * @return the cache used for incremental analysis or `null` if incremental analysis cannot
-   *         be performed
-   */
-  static IncrementalAnalysisCache update(
-      IncrementalAnalysisCache cache,
-      Source source,
-      String oldContents,
-      String newContents,
-      int offset,
-      int oldLength,
-      int newLength,
-      SourceEntry sourceEntry) {
-    // Determine the cache resolved unit
-    Source librarySource = null;
-    CompilationUnit unit = null;
-    if (sourceEntry is DartEntry) {
-      DartEntry dartEntry = sourceEntry;
-      List<Source> librarySources = dartEntry.librariesContaining;
-      if (librarySources.length == 1) {
-        librarySource = librarySources[0];
-        if (librarySource != null) {
-          unit = dartEntry.getValueInLibrary(
-              DartEntry.RESOLVED_UNIT, librarySource);
-        }
-      }
-    }
-    // Create a new cache if there is not an existing cache or the source is
-    // different or a new resolved compilation unit is available.
-    if (cache == null || cache.source != source || unit != null) {
-      if (unit == null) {
-        return null;
-      }
-      if (oldContents == null) {
-        if (oldLength != 0) {
-          return null;
-        }
-        oldContents =
-            "${newContents.substring(0, offset)}${newContents.substring(offset + newLength)}";
-      }
-      return new IncrementalAnalysisCache(librarySource, source, unit,
-          oldContents, newContents, offset, oldLength, newLength);
-    }
-    // Update the existing cache if the change is contiguous
-    if (cache._oldLength == 0 && cache._newLength == 0) {
-      cache._offset = offset;
-      cache._oldLength = oldLength;
-      cache._newLength = newLength;
-    } else {
-      if (cache._offset > offset || offset > cache._offset + cache._newLength) {
-        return null;
-      }
-      cache._newLength += newLength - oldLength;
-    }
-    cache._newContents = newContents;
-    return cache;
-  }
-
-  /**
-   * Verify that the incrementally parsed and resolved unit in the incremental cache is structurally
-   * equivalent to the fully parsed unit.
-   *
-   * @param cache the prior cache or `null` if none
-   * @param source the source of the compilation unit that was parsed (not `null`)
-   * @param unit the compilation unit that was just parsed
-   * @return the cache used for incremental analysis or `null` if incremental analysis results
-   *         cannot be cached for the next incremental analysis
-   */
-  static IncrementalAnalysisCache verifyStructure(
-      IncrementalAnalysisCache cache, Source source, CompilationUnit unit) {
-    if (cache != null && unit != null && cache.source == source) {
-      if (!AstComparator.equalNodes(cache.resolvedUnit, unit)) {
-        return null;
-      }
-    }
-    return cache;
-  }
-}
-
-/**
- * Instances of the class `IncrementalAnalysisTask` incrementally update existing analysis.
- */
-class IncrementalAnalysisTask extends AnalysisTask {
-  /**
-   * The information used to perform incremental analysis.
-   */
-  final IncrementalAnalysisCache cache;
-
-  /**
-   * The compilation unit that was produced by incrementally updating the existing unit.
-   */
-  CompilationUnit _updatedUnit;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param cache the incremental analysis cache used to perform the analysis
-   */
-  IncrementalAnalysisTask(InternalAnalysisContext context, this.cache)
-      : super(context);
-
-  /**
-   * Return the compilation unit that was produced by incrementally updating the existing
-   * compilation unit, or `null` if the task has not yet been performed, could not be
-   * performed, or if an exception occurred.
-   *
-   * @return the compilation unit
-   */
-  CompilationUnit get compilationUnit => _updatedUnit;
-
-  /**
-   * Return the source that is to be incrementally analyzed.
-   *
-   * @return the source
-   */
-  Source get source => cache != null ? cache.source : null;
-
-  @override
-  String get taskDescription =>
-      "incremental analysis ${cache != null ? cache.source : "null"}";
-
-  /**
-   * Return the type provider used for incremental resolution.
-   *
-   * @return the type provider (or `null` if an exception occurs)
-   */
-  TypeProvider get typeProvider {
-    try {
-      return context.typeProvider;
-    } on AnalysisException {
-      return null;
-    }
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitIncrementalAnalysisTask(this);
-
-  @override
-  void internalPerform() {
-    if (cache == null) {
-      return;
-    }
-    // Only handle small changes
-    if (cache.oldLength > 0 || cache.newLength > 30) {
-      return;
-    }
-    // Produce an updated token stream
-    CharacterReader reader = new CharSequenceReader(cache.newContents);
-    BooleanErrorListener errorListener = new BooleanErrorListener();
-    IncrementalScanner scanner = new IncrementalScanner(
-        cache.source, reader, errorListener, context.analysisOptions);
-    scanner.rescan(cache.resolvedUnit.beginToken, cache.offset, cache.oldLength,
-        cache.newLength);
-    if (errorListener.errorReported) {
-      return;
-    }
-    // Produce an updated AST
-    IncrementalParser parser = new IncrementalParser(
-        cache.source, scanner.tokenMap, AnalysisErrorListener.NULL_LISTENER);
-    _updatedUnit = parser.reparse(cache.resolvedUnit, scanner.leftToken,
-        scanner.rightToken, cache.offset, cache.offset + cache.oldLength);
-    // Update the resolution
-    TypeProvider typeProvider = this.typeProvider;
-    if (_updatedUnit != null && typeProvider != null) {
-      CompilationUnitElement element = _updatedUnit.element;
-      if (element != null) {
-        LibraryElement library = element.library;
-        if (library != null) {
-          IncrementalResolver resolver = new IncrementalResolver(null, null,
-              null, element, cache.offset, cache.oldLength, cache.newLength);
-          resolver.resolve(parser.updatedNode);
-        }
-      }
-    }
-  }
-}
-
-/**
  * Additional behavior for an analysis context that is required by internal
  * users of the context.
  */
 abstract class InternalAnalysisContext implements AnalysisContext {
   /**
    * A table mapping the sources known to the context to the information known
    * about the source.
    *
    * TODO(scheglov) add the type, once we have only one cache.
    */
   dynamic get analysisCache;
 
   /**
    * Allow the client to supply its own content cache.  This will take the
    * place of the content cache created by default, allowing clients to share
    * the content cache between contexts.
    */
   set contentCache(ContentCache value);
 
   /// Get the [EmbedderYamlLocator] for this context.
   EmbedderYamlLocator get embedderYamlLocator;
 
   /**
    * Return a list of the explicit targets being analyzed by this context.
    */
   List<AnalysisTarget> get explicitTargets;
 
   /**
-   * A factory to override how [LibraryResolver] is created.
-   */
-  LibraryResolverFactory get libraryResolverFactory;
-
-  /**
    * Return a list containing all of the sources that have been marked as
    * priority sources. Clients must not modify the returned list.
    */
   List<Source> get prioritySources;
 
   /**
    * Return a list of the priority targets being analyzed by this context.
    */
   List<AnalysisTarget> get priorityTargets;
 
   /**
    * The partition that contains analysis results that are not shared with other
    * contexts.
    *
    * TODO(scheglov) add the type, once we have only one cache.
    */
   dynamic get privateAnalysisCachePartition;
 
   /**
    * A factory to override how [ResolverVisitor] is created.
    */
   ResolverVisitorFactory get resolverVisitorFactory;
 
   /**
-   * Returns a statistics about this context.
-   */
-  AnalysisContextStatistics get statistics;
-
-  /**
    * Sets the [TypeProvider] for this context.
    */
   void set typeProvider(TypeProvider typeProvider);
 
   /**
    * A factory to override how [TypeResolverVisitor] is created.
    */
   TypeResolverVisitorFactory get typeResolverVisitorFactory;
 
   /**
    * A list of all [WorkManager]s used by this context.
    */
-  List<newContext.WorkManager> get workManagers;
+  List<WorkManager> get workManagers;
 
   /**
    * Return a list containing the sources of the libraries that are exported by
    * the library with the given [source]. The list will be empty if the given
    * source is invalid, if the given source does not represent a library, or if
    * the library does not export any other libraries.
    *
    * Throws an [AnalysisException] if the exported libraries could not be
    * computed.
    */
@@ skipping 24 matching lines @@
   /**
    * Return all the resolved [CompilationUnit]s for the given [source] if not
    * flushed, otherwise return `null` and ensures that the [CompilationUnit]s
    * will be eventually returned to the client from [performAnalysisTask].
    */
   List<CompilationUnit> ensureResolvedDartUnits(Source source);
 
   /**
    * Return the cache entry associated with the given [target].
    */
-  cache.CacheEntry getCacheEntry(AnalysisTarget target);
+  CacheEntry getCacheEntry(AnalysisTarget target);
 
   /**
    * Return context that owns the given [source].
    */
   InternalAnalysisContext getContextFor(Source source);
 
   /**
    * Return a change notice for the given [source], creating one if one does not
    * already exist.
    */
@@ skipping 26 matching lines @@
 
   /**
    * Given an [elementMap] mapping the source for the libraries represented by
    * the corresponding elements to the elements representing the libraries,
    * record those mappings.
    */
   void recordLibraryElements(Map<Source, LibraryElement> elementMap);
 
   /**
    * Return `true` if errors should be produced for the given [source].
-   * The [entry] associated with the source is passed in for efficiency.
-   *
-   * TODO(scheglov) remove [entry] after migration to the new task model.
-   * It is not used there anyway.
-   */
-  bool shouldErrorsBeAnalyzed(Source source, Object entry);
+   */
+  bool shouldErrorsBeAnalyzed(Source source);
 
   /**
    * For testing only: flush all representations of the AST (both resolved and
    * unresolved) for the given [source] out of the cache.
    */
   void test_flushAstStructures(Source source);
 
   /**
    * Call the given callback function for eache cache item in the context.
    */
   @deprecated
-  void visitCacheItems(void callback(Source source, SourceEntry dartEntry,
-      DataDescriptor rowDesc, CacheState state));
+  void visitCacheItems(void callback(
+      Source source, dynamic dartEntry, dynamic rowDesc, CacheState state));
 
   /**
    * Visit all entries of the content cache.
    */
   void visitContentCache(ContentCacheVisitor visitor);
 }
 
 /**
  * An object that can be used to receive information about errors within the
  * analysis engine. Implementations usually write this information to a file,
@@ skipping 74 matching lines @@
     this._source = source;
   }
 
   /**
    * Return the source that was removed while it was being analyzed.
    */
   Source get source => _source;
 }
 
 /**
- * Instances of the class `ParseDartTask` parse a specific source as a Dart file.
- */
-class ParseDartTask extends AnalysisTask {
-  /**
-   * The source to be parsed.
-   */
-  final Source source;
-
-  /**
-   * The head of the token stream used for parsing.
-   */
-  final Token _tokenStream;
-
-  /**
-   * The line information associated with the source.
-   */
-  final LineInfo lineInfo;
-
-  /**
-   * The compilation unit that was produced by parsing the source.
-   */
-  CompilationUnit _unit;
-
-  /**
-   * A flag indicating whether the source contains a 'part of' directive.
-   */
-  bool _containsPartOfDirective = false;
-
-  /**
-   * A flag indicating whether the source contains any directive other than a 'part of' directive.
-   */
-  bool _containsNonPartOfDirective = false;
-
-  /**
-   * A set containing the sources referenced by 'export' directives.
-   */
-  HashSet<Source> _exportedSources = new HashSet<Source>();
-
-  /**
-   * A set containing the sources referenced by 'import' directives.
-   */
-  HashSet<Source> _importedSources = new HashSet<Source>();
-
-  /**
-   * A set containing the sources referenced by 'part' directives.
-   */
-  HashSet<Source> _includedSources = new HashSet<Source>();
-
-  /**
-   * The errors that were produced by scanning and parsing the source.
-   */
-  List<AnalysisError> _errors = AnalysisError.NO_ERRORS;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be parsed
-   * @param tokenStream the head of the token stream used for parsing
-   * @param lineInfo the line information associated with the source
-   */
-  ParseDartTask(InternalAnalysisContext context, this.source, this._tokenStream,
-      this.lineInfo)
-      : super(context);
-
-  /**
-   * Return the compilation unit that was produced by parsing the source, or `null` if the
-   * task has not yet been performed or if an exception occurred.
-   *
-   * @return the compilation unit that was produced by parsing the source
-   */
-  CompilationUnit get compilationUnit => _unit;
-
-  /**
-   * Return the errors that were produced by scanning and parsing the source, or an empty list if
-   * the task has not yet been performed or if an exception occurred.
-   *
-   * @return the errors that were produced by scanning and parsing the source
-   */
-  List<AnalysisError> get errors => _errors;
-
-  /**
-   * Return a list containing the sources referenced by 'export' directives, or an empty list if
-   * the task has not yet been performed or if an exception occurred.
-   *
-   * @return an list containing the sources referenced by 'export' directives
-   */
-  List<Source> get exportedSources => _toArray(_exportedSources);
-
-  /**
-   * Return `true` if the source contains any directive other than a 'part of' directive, or
-   * `false` if the task has not yet been performed or if an exception occurred.
-   *
-   * @return `true` if the source contains any directive other than a 'part of' directive
-   */
-  bool get hasNonPartOfDirective => _containsNonPartOfDirective;
-
-  /**
-   * Return `true` if the source contains a 'part of' directive, or `false` if the task
-   * has not yet been performed or if an exception occurred.
-   *
-   * @return `true` if the source contains a 'part of' directive
-   */
-  bool get hasPartOfDirective => _containsPartOfDirective;
-
-  /**
-   * Return a list containing the sources referenced by 'import' directives, or an empty list if
-   * the task has not yet been performed or if an exception occurred.
-   *
-   * @return a list containing the sources referenced by 'import' directives
-   */
-  List<Source> get importedSources => _toArray(_importedSources);
-
-  /**
-   * Return a list containing the sources referenced by 'part' directives, or an empty list if
-   * the task has not yet been performed or if an exception occurred.
-   *
-   * @return a list containing the sources referenced by 'part' directives
-   */
-  List<Source> get includedSources => _toArray(_includedSources);
-
-  @override
-  String get taskDescription {
-    if (source == null) {
-      return "parse as dart null source";
-    }
-    return "parse as dart ${source.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitParseDartTask(this);
-
-  @override
-  void internalPerform() {
-    //
-    // Then parse the token stream.
-    //
-    PerformanceStatistics.parse.makeCurrentWhile(() {
-      RecordingErrorListener errorListener = new RecordingErrorListener();
-      Parser parser = new Parser(source, errorListener);
-      AnalysisOptions options = context.analysisOptions;
-      parser.parseFunctionBodies =
-          options.analyzeFunctionBodiesPredicate(source);
-      parser.parseGenericMethods = options.enableGenericMethods;
-      _unit = parser.parseCompilationUnit(_tokenStream);
-      _unit.lineInfo = lineInfo;
-      AnalysisContext analysisContext = context;
-      for (Directive directive in _unit.directives) {
-        if (directive is PartOfDirective) {
-          _containsPartOfDirective = true;
-        } else {
-          _containsNonPartOfDirective = true;
-          if (directive is UriBasedDirective) {
-            Source referencedSource = resolveDirective(
-                analysisContext, source, directive, errorListener);
-            if (referencedSource != null) {
-              if (directive is ExportDirective) {
-                _exportedSources.add(referencedSource);
-              } else if (directive is ImportDirective) {
-                _importedSources.add(referencedSource);
-              } else if (directive is PartDirective) {
-                if (referencedSource != source) {
-                  _includedSources.add(referencedSource);
-                }
-              } else {
-                throw new AnalysisException(
-                    "$runtimeType failed to handle a ${directive.runtimeType}");
-              }
-            }
-          }
-        }
-      }
-      _errors = errorListener.getErrorsForSource(source);
-    });
-  }
-
-  /**
-   * Efficiently convert the given set of [sources] to a list.
-   */
-  List<Source> _toArray(HashSet<Source> sources) {
-    int size = sources.length;
-    if (size == 0) {
-      return Source.EMPTY_LIST;
-    }
-    return new List.from(sources);
-  }
-
-  /**
-   * Return the result of resolving the URI of the given URI-based directive against the URI of the
-   * given library, or `null` if the URI is not valid.
-   *
-   * @param context the context in which the resolution is to be performed
-   * @param librarySource the source representing the library containing the directive
-   * @param directive the directive which URI should be resolved
-   * @param errorListener the error listener to which errors should be reported
-   * @return the result of resolving the URI against the URI of the library
-   */
-  static Source resolveDirective(AnalysisContext context, Source librarySource,
-      UriBasedDirective directive, AnalysisErrorListener errorListener) {
-    StringLiteral uriLiteral = directive.uri;
-    String uriContent = uriLiteral.stringValue;
-    if (uriContent != null) {
-      uriContent = uriContent.trim();
-      directive.uriContent = uriContent;
-    }
-    UriValidationCode code = directive.validate();
-    if (code == null) {
-      String encodedUriContent = Uri.encodeFull(uriContent);
-      try {
-        Source source =
-            context.sourceFactory.resolveUri(librarySource, encodedUriContent);
-        directive.source = source;
-        return source;
-      } on JavaIOException {
-        code = UriValidationCode.INVALID_URI;
-      }
-    }
-    if (code == UriValidationCode.URI_WITH_DART_EXT_SCHEME) {
-      return null;
-    }
-    if (code == UriValidationCode.URI_WITH_INTERPOLATION) {
-      errorListener.onError(new AnalysisError(librarySource, uriLiteral.offset,
-          uriLiteral.length, CompileTimeErrorCode.URI_WITH_INTERPOLATION));
-      return null;
-    }
-    if (code == UriValidationCode.INVALID_URI) {
-      errorListener.onError(new AnalysisError(librarySource, uriLiteral.offset,
-          uriLiteral.length, CompileTimeErrorCode.INVALID_URI, [uriContent]));
-      return null;
-    }
-    throw new RuntimeException(
-        message: "Failed to handle validation code: $code");
-  }
-}
-
-/**
- * Instances of the class `ParseHtmlTask` parse a specific source as an HTML file.
- */
-class ParseHtmlTask extends AnalysisTask {
-  /**
-   * The name of the 'src' attribute in a HTML tag.
-   */
-  static String _ATTRIBUTE_SRC = "src";
-
-  /**
-   * The name of the 'script' tag in an HTML file.
-   */
-  static String _TAG_SCRIPT = "script";
-
-  /**
-   * The source to be parsed.
-   */
-  final Source source;
-
-  /**
-   * The contents of the source.
-   */
-  final String _content;
-
-  /**
-   * The line information that was produced.
-   */
-  LineInfo _lineInfo;
-
-  /**
-   * The HTML unit that was produced by parsing the source.
-   */
-  ht.HtmlUnit _unit;
-
-  /**
-   * The errors that were produced by scanning and parsing the source.
-   */
-  List<AnalysisError> _errors = AnalysisError.NO_ERRORS;
-
-  /**
-   * A list containing the sources of the libraries that are referenced within the HTML.
-   */
-  List<Source> _referencedLibraries = Source.EMPTY_LIST;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be parsed
-   * @param content the contents of the source
-   */
-  ParseHtmlTask(InternalAnalysisContext context, this.source, this._content)
-      : super(context);
-
-  /**
-   * Return the errors that were produced by scanning and parsing the source, or `null` if the
-   * task has not yet been performed or if an exception occurred.
-   *
-   * @return the errors that were produced by scanning and parsing the source
-   */
-  List<AnalysisError> get errors => _errors;
-
-  /**
-   * Return the HTML unit that was produced by parsing the source.
-   *
-   * @return the HTML unit that was produced by parsing the source
-   */
-  ht.HtmlUnit get htmlUnit => _unit;
-
-  /**
-   * Return the sources of libraries that are referenced in the specified HTML file.
-   *
-   * @return the sources of libraries that are referenced in the HTML file
-   */
-  List<Source> get librarySources {
-    List<Source> libraries = new List<Source>();
-    _unit.accept(new ParseHtmlTask_getLibrarySources(this, libraries));
-    if (libraries.isEmpty) {
-      return Source.EMPTY_LIST;
-    }
-    return libraries;
-  }
-
-  /**
-   * Return the line information that was produced, or `null` if the task has not yet been
-   * performed or if an exception occurred.
-   *
-   * @return the line information that was produced
-   */
-  LineInfo get lineInfo => _lineInfo;
-
-  /**
-   * Return a list containing the sources of the libraries that are referenced within the HTML.
-   *
-   * @return the sources of the libraries that are referenced within the HTML
-   */
-  List<Source> get referencedLibraries => _referencedLibraries;
-
-  @override
-  String get taskDescription {
-    if (source == null) {
-      return "parse as html null source";
-    }
-    return "parse as html ${source.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitParseHtmlTask(this);
-
-  @override
-  void internalPerform() {
-    try {
-      ht.AbstractScanner scanner = new ht.StringScanner(source, _content);
-      scanner.passThroughElements = <String>[_TAG_SCRIPT];
-      ht.Token token = scanner.tokenize();
-      _lineInfo = new LineInfo(scanner.lineStarts);
-      RecordingErrorListener errorListener = new RecordingErrorListener();
-      _unit = new ht.HtmlParser(source, errorListener, context.analysisOptions)
-          .parse(token, _lineInfo);
-      _unit.accept(new RecursiveXmlVisitor_ParseHtmlTask_internalPerform(
-          this, errorListener));
-      _errors = errorListener.getErrorsForSource(source);
-      _referencedLibraries = librarySources;
-    } catch (exception, stackTrace) {
-      throw new AnalysisException(
-          "Exception", new CaughtException(exception, stackTrace));
-    }
-  }
-
-  /**
-   * Resolves directives in the given [CompilationUnit].
-   */
-  void _resolveScriptDirectives(
-      CompilationUnit script, AnalysisErrorListener errorListener) {
-    if (script == null) {
-      return;
-    }
-    AnalysisContext analysisContext = context;
-    for (Directive directive in script.directives) {
-      if (directive is UriBasedDirective) {
-        ParseDartTask.resolveDirective(
-            analysisContext, source, directive, errorListener);
-      }
-    }
-  }
-}
-
-class ParseHtmlTask_getLibrarySources extends ht.RecursiveXmlVisitor<Object> {
-  final ParseHtmlTask _task;
-
-  List<Source> libraries;
-
-  ParseHtmlTask_getLibrarySources(this._task, this.libraries) : super();
-
-  @override
-  Object visitHtmlScriptTagNode(ht.HtmlScriptTagNode node) {
-    ht.XmlAttributeNode scriptAttribute = null;
-    for (ht.XmlAttributeNode attribute in node.attributes) {
-      if (javaStringEqualsIgnoreCase(
-          attribute.name, ParseHtmlTask._ATTRIBUTE_SRC)) {
-        scriptAttribute = attribute;
-      }
-    }
-    if (scriptAttribute != null) {
-      try {
-        Uri uri = Uri.parse(scriptAttribute.text);
-        String fileName = uri.path;
-        Source librarySource =
-            _task.context.sourceFactory.resolveUri(_task.source, fileName);
-        if (_task.context.exists(librarySource)) {
-          libraries.add(librarySource);
-        }
-      } on FormatException {
-        // ignored - invalid URI reported during resolution phase
-      }
-    }
-    return super.visitHtmlScriptTagNode(node);
-  }
-}
-
-/**
- * An object that manages the partitions that can be shared between analysis
- * contexts.
- */
-class PartitionManager {
-  /**
-   * The default cache size for a Dart SDK partition.
-   */
-  static int _DEFAULT_SDK_CACHE_SIZE = 256;
-
-  /**
-   * A table mapping SDK's to the partitions used for those SDK's.
-   */
-  HashMap<DartSdk, SdkCachePartition> _sdkPartitions =
-      new HashMap<DartSdk, SdkCachePartition>();
-
-  /**
-   * Clear any cached data being maintained by this manager.
-   */
-  void clearCache() {
-    _sdkPartitions.clear();
-  }
-
-  /**
-   * Return the partition being used for the given [sdk], creating the partition
-   * if necessary.
-   */
-  SdkCachePartition forSdk(DartSdk sdk) {
-    // Call sdk.context now, because when it creates a new
-    // InternalAnalysisContext instance, it calls forSdk() again, so creates an
-    // SdkCachePartition instance.
-    // So, if we initialize context after "partition == null", we end up
-    // with two SdkCachePartition instances.
-    InternalAnalysisContext sdkContext = sdk.context;
-    // Check cache for an existing partition.
-    SdkCachePartition partition = _sdkPartitions[sdk];
-    if (partition == null) {
-      partition = new SdkCachePartition(sdkContext, _DEFAULT_SDK_CACHE_SIZE);
-      _sdkPartitions[sdk] = partition;
-    }
-    return partition;
-  }
-}
-
-/**
- * Representation of a pending computation which is based on the results of
- * analysis that may or may not have been completed.
- */
-class PendingFuture<T> {
-  /**
-   * The context in which this computation runs.
-   */
-  final AnalysisContextImpl _context;
-
-  /**
-   * The source used by this computation to compute its value.
-   */
-  final Source source;
-
-  /**
-   * The function which implements the computation.
-   */
-  final PendingFutureComputer<T> _computeValue;
-
-  /**
-   * The completer that should be completed once the computation has succeeded.
-   */
-  CancelableCompleter<T> _completer;
-
-  PendingFuture(this._context, this.source, this._computeValue) {
-    _completer = new CancelableCompleter<T>(_onCancel);
-  }
-
-  /**
-   * Retrieve the future which will be completed when this object is
-   * successfully evaluated.
-   */
-  CancelableFuture<T> get future => _completer.future;
-
-  /**
-   * Execute [_computeValue], passing it the given [sourceEntry], and complete
-   * the pending future if it's appropriate to do so.  If the pending future is
-   * completed by this call, true is returned; otherwise false is returned.
-   *
-   * Once this function has returned true, it should not be called again.
-   *
-   * Other than completing the future, this method is free of side effects.
-   * Note that any code the client has attached to the future will be executed
-   * in a microtask, so there is no danger of side effects occurring due to
-   * client callbacks.
-   */
-  bool evaluate(SourceEntry sourceEntry) {
-    assert(!_completer.isCompleted);
-    try {
-      T result = _computeValue(sourceEntry);
-      if (result == null) {
-        return false;
-      } else {
-        _completer.complete(result);
-        return true;
-      }
-    } catch (exception, stackTrace) {
-      _completer.completeError(exception, stackTrace);
-      return true;
-    }
-  }
-
-  /**
-   * No further analysis updates are expected which affect this future, so
-   * complete it with an AnalysisNotScheduledError in order to avoid
-   * deadlocking the client.
-   */
-  void forciblyComplete() {
-    try {
-      throw new AnalysisNotScheduledError();
-    } catch (exception, stackTrace) {
-      _completer.completeError(exception, stackTrace);
-    }
-  }
-
-  void _onCancel() {
-    _context._cancelFuture(this);
-  }
-}
-
-/**
  * Container with global [AnalysisContext] performance statistics.
  */
 class PerformanceStatistics {
   /**
    * The [PerformanceTag] for time spent in reading files.
    */
   static PerformanceTag io = new PerformanceTag('io');
 
   /**
    * The [PerformanceTag] for time spent in scanning.
@@ skipping 109 matching lines @@
     Source source = error.source;
     HashSet<AnalysisError> errorsForSource = _errors[source];
     if (_errors[source] == null) {
       errorsForSource = new HashSet<AnalysisError>();
       _errors[source] = errorsForSource;
     }
     errorsForSource.add(error);
   }
 }
 
-class RecursiveXmlVisitor_ParseHtmlTask_internalPerform
-    extends ht.RecursiveXmlVisitor<Object> {
-  final ParseHtmlTask ParseHtmlTask_this;
-
-  RecordingErrorListener errorListener;
-
-  RecursiveXmlVisitor_ParseHtmlTask_internalPerform(
-      this.ParseHtmlTask_this, this.errorListener)
-      : super();
-
-  @override
-  Object visitHtmlScriptTagNode(ht.HtmlScriptTagNode node) {
-    ParseHtmlTask_this._resolveScriptDirectives(node.script, errorListener);
-    return null;
-  }
-}
-
-class RecursiveXmlVisitor_ResolveHtmlTask_internalPerform
-    extends ht.RecursiveXmlVisitor<Object> {
-  final ResolveHtmlTask ResolveHtmlTask_this;
-
-  RecordingErrorListener errorListener;
-
-  RecursiveXmlVisitor_ResolveHtmlTask_internalPerform(
-      this.ResolveHtmlTask_this, this.errorListener)
-      : super();
-
-  @override
-  Object visitHtmlScriptTagNode(ht.HtmlScriptTagNode node) {
-    CompilationUnit script = node.script;
-    if (script != null) {
-      GenerateDartErrorsTask.validateDirectives(ResolveHtmlTask_this.context,
-          ResolveHtmlTask_this.source, script, errorListener);
-    }
-    return null;
-  }
-}
-
 /**
  * An visitor that removes any resolution information from an AST structure when
  * used to visit that structure.
  */
 class ResolutionEraser extends GeneralizingAstVisitor<Object> {
   /**
    * A flag indicating whether the elements associated with declarations should
    * be erased.
    */
   bool eraseDeclarations = true;
@@ skipping 129 matching lines @@
    * Remove any resolution information from the given AST structure.
    */
   static void erase(AstNode node, {bool eraseDeclarations: true}) {
     ResolutionEraser eraser = new ResolutionEraser();
     eraser.eraseDeclarations = eraseDeclarations;
     node.accept(eraser);
   }
 }
 
 /**
- * The information produced by resolving a compilation unit as part of a
- * specific library.
- */
-class ResolutionState {
-  /**
-   * The next resolution state or `null` if none.
-   */
-  ResolutionState _nextState;
-
-  /**
-   * The source for the defining compilation unit of the library that contains
-   * this unit. If this unit is the defining compilation unit for it's library,
-   * then this will be the source for this unit.
-   */
-  Source _librarySource;
-
-  /**
-   * A table mapping descriptors to the cached results for those descriptors.
-   * If there is no entry for a given descriptor then the state is implicitly
-   * [CacheState.INVALID] and the value is implicitly the default value.
-   */
-  Map<DataDescriptor, CachedResult> resultMap =
-      new HashMap<DataDescriptor, CachedResult>();
-
-  /**
-   * Flush any AST structures being maintained by this state.
-   */
-  void flushAstStructures() {
-    _flush(DartEntry.BUILT_UNIT);
-    _flush(DartEntry.RESOLVED_UNIT);
-    if (_nextState != null) {
-      _nextState.flushAstStructures();
-    }
-  }
-
-  /**
-   * Return the state of the data represented by the given [descriptor].
-   */
-  CacheState getState(DataDescriptor descriptor) {
-    CachedResult result = resultMap[descriptor];
-    if (result == null) {
-      return CacheState.INVALID;
-    }
-    return result.state;
-  }
-
-  /**
-   * Return the value of the data represented by the given [descriptor], or
-   * `null` if the data represented by the descriptor is not valid.
-   */
-  /*<V>*/ dynamic /*V*/ getValue(DataDescriptor /*<V>*/ descriptor) {
-    CachedResult result = resultMap[descriptor];
-    if (result == null) {
-      return descriptor.defaultValue;
-    }
-    return result.value;
-  }
-
-  /**
-   * Return `true` if the state of any data value is [CacheState.ERROR].
-   */
-  bool hasErrorState() {
-    for (CachedResult result in resultMap.values) {
-      if (result.state == CacheState.ERROR) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Invalidate all of the resolution information associated with the compilation unit.
-   */
-  void invalidateAllResolutionInformation() {
-    _nextState = null;
-    _librarySource = null;
-    setState(DartEntry.BUILT_UNIT, CacheState.INVALID);
-    setState(DartEntry.BUILT_ELEMENT, CacheState.INVALID);
-    setState(DartEntry.HINTS, CacheState.INVALID);
-    setState(DartEntry.LINTS, CacheState.INVALID);
-    setState(DartEntry.RESOLVED_UNIT, CacheState.INVALID);
-    setState(DartEntry.RESOLUTION_ERRORS, CacheState.INVALID);
-    setState(DartEntry.VERIFICATION_ERRORS, CacheState.INVALID);
-  }
-
-  /**
-   * Record that an exception occurred while attempting to build the element
-   * model for the source associated with this state.
-   */
-  void recordBuildElementError() {
-    setState(DartEntry.BUILT_UNIT, CacheState.ERROR);
-    setState(DartEntry.BUILT_ELEMENT, CacheState.ERROR);
-    recordResolutionError();
-  }
-
-  /**
-   * Record that an exception occurred while attempting to generate hints for
-   * the source associated with this entry. This will set the state of all
-   * verification information as being in error.
-   */
-  void recordHintError() {
-    setState(DartEntry.HINTS, CacheState.ERROR);
-  }
-
-  /**
-   * Record that an exception occurred while attempting to generate lints for
-   * the source associated with this entry. This will set the state of all
-   * verification information as being in error.
-   */
-  void recordLintError() {
-    setState(DartEntry.LINTS, CacheState.ERROR);
-  }
-
-  /**
-   * Record that an exception occurred while attempting to resolve the source
-   * associated with this state.
-   */
-  void recordResolutionError() {
-    setState(DartEntry.RESOLVED_UNIT, CacheState.ERROR);
-    setState(DartEntry.RESOLUTION_ERRORS, CacheState.ERROR);
-    recordVerificationError();
-  }
-
-  /**
-   * Record that an exception occurred while attempting to scan or parse the
-   * source associated with this entry. This will set the state of all
-   * resolution-based information as being in error.
-   */
-  void recordResolutionErrorsInAllLibraries() {
-    recordBuildElementError();
-    if (_nextState != null) {
-      _nextState.recordResolutionErrorsInAllLibraries();
-    }
-  }
-
-  /**
-   * Record that an exception occurred while attempting to generate errors and
-   * warnings for the source associated with this entry. This will set the state
-   * of all verification information as being in error.
-   */
-  void recordVerificationError() {
-    setState(DartEntry.VERIFICATION_ERRORS, CacheState.ERROR);
-    recordHintError();
-  }
-
-  /**
-   * Set the state of the data represented by the given [descriptor] to the
-   * given [state].
-   */
-  void setState(DataDescriptor descriptor, CacheState state) {
-    if (state == CacheState.VALID) {
-      throw new ArgumentError("use setValue() to set the state to VALID");
-    }
-    if (state == CacheState.INVALID) {
-      resultMap.remove(descriptor);
-    } else {
-      CachedResult result =
-          resultMap.putIfAbsent(descriptor, () => new CachedResult(descriptor));
-      result.state = state;
-      if (state != CacheState.IN_PROCESS) {
-        //
-        // If the state is in-process, we can leave the current value in the
-        // cache for any 'get' methods to access.
-        //
-        result.value = descriptor.defaultValue;
-      }
-    }
-  }
-
-  /**
-   * Set the value of the data represented by the given [descriptor] to the
-   * given [value].
-   */
-  void setValue(DataDescriptor /*<V>*/ descriptor, dynamic /*V*/ value) {
-    CachedResult result =
-        resultMap.putIfAbsent(descriptor, () => new CachedResult(descriptor));
-    SourceEntry.countTransition(descriptor, result);
-    result.state = CacheState.VALID;
-    result.value = value == null ? descriptor.defaultValue : value;
-  }
-
-  /**
-   * Flush the value of the data described by the [descriptor].
-   */
-  void _flush(DataDescriptor descriptor) {
-    CachedResult result = resultMap[descriptor];
-    if (result != null && result.state == CacheState.VALID) {
-      result.state = CacheState.FLUSHED;
-      result.value = descriptor.defaultValue;
-    }
-  }
-
-  /**
-   * Write a textual representation of the difference between the old entry and
-   * this entry to the given string [buffer]. A separator will be written before
-   * the first difference if [needsSeparator] is `true`. The [oldEntry] is the
-   * entry that was replaced by this entry. Return `true` is a separator is
-   * needed before writing any subsequent differences.
-   */
-  bool _writeDiffOn(
-      StringBuffer buffer, bool needsSeparator, DartEntry oldEntry) {
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator, "resolvedUnit",
-        DartEntry.RESOLVED_UNIT, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "resolutionErrors", DartEntry.RESOLUTION_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(buffer, needsSeparator,
-        "verificationErrors", DartEntry.VERIFICATION_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "hints", DartEntry.HINTS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "lints", DartEntry.LINTS, oldEntry);
-    return needsSeparator;
-  }
-
-  /**
-   * Write a textual representation of this state to the given [buffer]. The
-   * result will only be used for debugging purposes.
-   */
-  void _writeOn(StringBuffer buffer) {
-    if (_librarySource != null) {
-      _writeStateOn(buffer, "builtElement", DartEntry.BUILT_ELEMENT);
-      _writeStateOn(buffer, "builtUnit", DartEntry.BUILT_UNIT);
-      _writeStateOn(buffer, "resolvedUnit", DartEntry.RESOLVED_UNIT);
-      _writeStateOn(buffer, "resolutionErrors", DartEntry.RESOLUTION_ERRORS);
-      _writeStateOn(
-          buffer, "verificationErrors", DartEntry.VERIFICATION_ERRORS);
-      _writeStateOn(buffer, "hints", DartEntry.HINTS);
-      _writeStateOn(buffer, "lints", DartEntry.LINTS);
-      if (_nextState != null) {
-        _nextState._writeOn(buffer);
-      }
-    }
-  }
-
-  /**
-   * Write a textual representation of the difference between the state of the
-   * value described by the given [descriptor] between the [oldEntry] and this
-   * entry to the given [buffer]. Return `true` if some difference was written.
-   */
-  bool _writeStateDiffOn(StringBuffer buffer, bool needsSeparator, String label,
-      DataDescriptor descriptor, SourceEntry oldEntry) {
-    CacheState oldState = oldEntry.getState(descriptor);
-    CacheState newState = getState(descriptor);
-    if (oldState != newState) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write(label);
-      buffer.write(" = ");
-      buffer.write(oldState);
-      buffer.write(" -> ");
-      buffer.write(newState);
-      return true;
-    }
-    return needsSeparator;
-  }
-
-  /**
-   * Write a textual representation of the state of the value described by the
-   * given [descriptor] to the given bugger, prefixed by the given [label] to
-   * the given [buffer].
-   */
-  void _writeStateOn(
-      StringBuffer buffer, String label, DataDescriptor descriptor) {
-    CachedResult result = resultMap[descriptor];
-    buffer.write("; ");
-    buffer.write(label);
-    buffer.write(" = ");
-    buffer.write(result == null ? CacheState.INVALID : result.state);
-  }
-}
-
-/**
- * A compilation unit that is not referenced by any other objects. It is used by
- * the [LibraryResolver] to resolve a library.
- */
-class ResolvableCompilationUnit {
-  /**
-   * The source of the compilation unit.
-   */
-  final Source source;
-
-  /**
-   * The compilation unit.
-   */
-  final CompilationUnit compilationUnit;
-
-  /**
-   * Initialize a newly created holder to hold the given [source] and
-   * [compilationUnit].
-   */
-  ResolvableCompilationUnit(this.source, this.compilationUnit);
-}
-
-/**
- * Instances of the class `ResolveDartLibraryTask` resolve a specific Dart library.
- */
-class ResolveDartLibraryCycleTask extends AnalysisTask {
-  /**
-   * The source representing the file whose compilation unit is to be returned. TODO(brianwilkerson)
-   * This should probably be removed, but is being left in for now to ease the transition.
-   */
-  final Source unitSource;
-
-  /**
-   * The source representing the library to be resolved.
-   */
-  final Source librarySource;
-
-  /**
-   * The libraries that are part of the cycle containing the library to be resolved.
-   */
-  final List<ResolvableLibrary> _librariesInCycle;
-
-  /**
-   * The library resolver holding information about the libraries that were resolved.
-   */
-  LibraryResolver2 _resolver;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param unitSource the source representing the file whose compilation unit is to be returned
-   * @param librarySource the source representing the library to be resolved
-   * @param librariesInCycle the libraries that are part of the cycle containing the library to be
-   *          resolved
-   */
-  ResolveDartLibraryCycleTask(InternalAnalysisContext context, this.unitSource,
-      this.librarySource, this._librariesInCycle)
-      : super(context);
-
-  /**
-   * Return the library resolver holding information about the libraries that were resolved.
-   *
-   * @return the library resolver holding information about the libraries that were resolved
-   */
-  LibraryResolver2 get libraryResolver => _resolver;
-
-  @override
-  String get taskDescription {
-    if (librarySource == null) {
-      return "resolve library null source";
-    }
-    return "resolve library ${librarySource.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitResolveDartLibraryCycleTask(this);
-
-  @override
-  void internalPerform() {
-    _resolver = new LibraryResolver2(context);
-    _resolver.resolveLibrary(librarySource, _librariesInCycle);
-  }
-}
-
-/**
- * Instances of the class `ResolveDartLibraryTask` resolve a specific Dart library.
- */
-class ResolveDartLibraryTask extends AnalysisTask {
-  /**
-   * The source representing the file whose compilation unit is to be returned.
-   */
-  final Source unitSource;
-
-  /**
-   * The source representing the library to be resolved.
-   */
-  final Source librarySource;
-
-  /**
-   * The library resolver holding information about the libraries that were resolved.
-   */
-  LibraryResolver _resolver;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param unitSource the source representing the file whose compilation unit is to be returned
-   * @param librarySource the source representing the library to be resolved
-   */
-  ResolveDartLibraryTask(
-      InternalAnalysisContext context, this.unitSource, this.librarySource)
-      : super(context);
-
-  /**
-   * Return the library resolver holding information about the libraries that were resolved.
-   *
-   * @return the library resolver holding information about the libraries that were resolved
-   */
-  LibraryResolver get libraryResolver => _resolver;
-
-  @override
-  String get taskDescription {
-    if (librarySource == null) {
-      return "resolve library null source";
-    }
-    return "resolve library ${librarySource.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) =>
-      visitor.visitResolveDartLibraryTask(this);
-
-  @override
-  void internalPerform() {
-    LibraryResolverFactory resolverFactory = context.libraryResolverFactory;
-    _resolver = resolverFactory == null
-        ? new LibraryResolver(context)
-        : resolverFactory(context);
-    _resolver.resolveLibrary(librarySource, true);
-  }
-}
-
-/**
- * Instances of the class `ResolveDartUnitTask` resolve a single Dart file based on a existing
- * element model.
- */
-class ResolveDartUnitTask extends AnalysisTask {
-  /**
-   * The source that is to be resolved.
-   */
-  final Source source;
-
-  /**
-   * The element model for the library containing the source.
-   */
-  final LibraryElement _libraryElement;
-
-  /**
-   * The compilation unit that was resolved by this task.
-   */
-  CompilationUnit _resolvedUnit;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be parsed
-   * @param libraryElement the element model for the library containing the source
-   */
-  ResolveDartUnitTask(
-      InternalAnalysisContext context, this.source, this._libraryElement)
-      : super(context);
-
-  /**
-   * Return the source for the library containing the source that is to be resolved.
-   *
-   * @return the source for the library containing the source that is to be resolved
-   */
-  Source get librarySource => _libraryElement.source;
-
-  /**
-   * Return the compilation unit that was resolved by this task.
-   *
-   * @return the compilation unit that was resolved by this task
-   */
-  CompilationUnit get resolvedUnit => _resolvedUnit;
-
-  @override
-  String get taskDescription {
-    Source librarySource = _libraryElement.source;
-    if (librarySource == null) {
-      return "resolve unit null source";
-    }
-    return "resolve unit ${librarySource.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitResolveDartUnitTask(this);
-
-  @override
-  void internalPerform() {
-    TypeProvider typeProvider = _libraryElement.context.typeProvider;
-    CompilationUnit unit = context.computeResolvableCompilationUnit(source);
-    if (unit == null) {
-      throw new AnalysisException(
-          "Internal error: computeResolvableCompilationUnit returned a value without a parsed Dart unit");
-    }
-    //
-    // Resolve names in declarations.
-    //
-    new DeclarationResolver().resolve(unit, _find(_libraryElement, source));
-    //
-    // Resolve the type names.
-    //
-    RecordingErrorListener errorListener = new RecordingErrorListener();
-    TypeResolverVisitor typeResolverVisitor = new TypeResolverVisitor(
-        _libraryElement, source, typeProvider, errorListener);
-    unit.accept(typeResolverVisitor);
-    //
-    // Resolve the rest of the structure
-    //
-    InheritanceManager inheritanceManager =
-        new InheritanceManager(_libraryElement);
-    ResolverVisitor resolverVisitor = new ResolverVisitor(
-        _libraryElement, source, typeProvider, errorListener,
-        inheritanceManager: inheritanceManager);
-    unit.accept(resolverVisitor);
-    //
-    // Perform additional error checking.
-    //
-    PerformanceStatistics.errors.makeCurrentWhile(() {
-      ErrorReporter errorReporter = new ErrorReporter(errorListener, source);
-      ErrorVerifier errorVerifier = new ErrorVerifier(
-          errorReporter,
-          _libraryElement,
-          typeProvider,
-          inheritanceManager,
-          context.analysisOptions.enableSuperMixins,
-          context.analysisOptions.enableAssertMessage);
-      unit.accept(errorVerifier);
-      // TODO(paulberry): as a temporary workaround for issue 21572,
-      // ConstantVerifier is being run right after ConstantValueComputer, so we
-      // don't need to run it here.  Once issue 21572 is fixed, re-enable the
-      // call to ConstantVerifier.
-//       ConstantVerifier constantVerifier = new ConstantVerifier(errorReporter, _libraryElement, typeProvider);
-//       unit.accept(constantVerifier);
-    });
-    //
-    // Capture the results.
-    //
-    _resolvedUnit = unit;
-  }
-
-  /**
-   * Search the compilation units that are part of the given library and return the element
-   * representing the compilation unit with the given source. Return `null` if there is no
-   * such compilation unit.
-   *
-   * @param libraryElement the element representing the library being searched through
-   * @param unitSource the source for the compilation unit whose element is to be returned
-   * @return the element representing the compilation unit
-   */
-  CompilationUnitElement _find(
-      LibraryElement libraryElement, Source unitSource) {
-    CompilationUnitElement element = libraryElement.definingCompilationUnit;
-    if (element.source == unitSource) {
-      return element;
-    }
-    for (CompilationUnitElement partElement in libraryElement.parts) {
-      if (partElement.source == unitSource) {
-        return partElement;
-      }
-    }
-    return null;
-  }
-}
-
-/**
- * Instances of the class `ResolveHtmlTask` resolve a specific source as an HTML file.
- */
-class ResolveHtmlTask extends AnalysisTask {
-  /**
-   * The source to be resolved.
-   */
-  final Source source;
-
-  /**
-   * The time at which the contents of the source were last modified.
-   */
-  final int modificationTime;
-
-  /**
-   * The HTML unit to be resolved.
-   */
-  final ht.HtmlUnit _unit;
-
-  /**
-   * The [HtmlUnit] that was resolved by this task.
-   */
-  ht.HtmlUnit _resolvedUnit;
-
-  /**
-   * The element produced by resolving the source.
-   */
-  HtmlElement _element = null;
-
-  /**
-   * The resolution errors that were discovered while resolving the source.
-   */
-  List<AnalysisError> _resolutionErrors = AnalysisError.NO_ERRORS;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be resolved
-   * @param modificationTime the time at which the contents of the source were last modified
-   * @param unit the HTML unit to be resolved
-   */
-  ResolveHtmlTask(InternalAnalysisContext context, this.source,
-      this.modificationTime, this._unit)
-      : super(context);
-
-  HtmlElement get element => _element;
-
-  List<AnalysisError> get resolutionErrors => _resolutionErrors;
-
-  /**
-   * Return the [HtmlUnit] that was resolved by this task.
-   *
-   * @return the [HtmlUnit] that was resolved by this task
-   */
-  ht.HtmlUnit get resolvedUnit => _resolvedUnit;
-
-  @override
-  String get taskDescription {
-    if (source == null) {
-      return "resolve as html null source";
-    }
-    return "resolve as html ${source.fullName}";
-  }
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitResolveHtmlTask(this);
-
-  @override
-  void internalPerform() {
-    //
-    // Build the standard HTML element.
-    //
-    HtmlUnitBuilder builder = new HtmlUnitBuilder(context);
-    _element = builder.buildHtmlElement(source, _unit);
-    RecordingErrorListener errorListener = builder.errorListener;
-    //
-    // Validate the directives
-    //
-    _unit.accept(new RecursiveXmlVisitor_ResolveHtmlTask_internalPerform(
-        this, errorListener));
-    //
-    // Record all resolution errors.
-    //
-    _resolutionErrors = errorListener.getErrorsForSource(source);
-    //
-    // Remember the resolved unit.
-    //
-    _resolvedUnit = _unit;
-  }
-}
-
-/**
- * The priority of data in the cache in terms of the desirability of retaining
- * some specified data about a specified source.
- */
-class RetentionPriority extends Enum<RetentionPriority> {
-  /**
-   * A priority indicating that a given piece of data can be removed from the
-   * cache without reservation.
-   */
-  static const RetentionPriority LOW = const RetentionPriority('LOW', 0);
-
-  /**
-   * A priority indicating that a given piece of data should not be removed from
-   * the cache unless there are no sources for which the corresponding data has
-   * a lower priority. Currently used for data that is needed in order to finish
-   * some outstanding analysis task.
-   */
-  static const RetentionPriority MEDIUM = const RetentionPriority('MEDIUM', 1);
-
-  /**
-   * A priority indicating that a given piece of data should not be removed from
-   * the cache. Currently used for data related to a priority source.
-   */
-  static const RetentionPriority HIGH = const RetentionPriority('HIGH', 2);
-
-  static const List<RetentionPriority> values = const [LOW, MEDIUM, HIGH];
-
-  const RetentionPriority(String name, int ordinal) : super(name, ordinal);
-}
-
-/**
- * Instances of the class `ScanDartTask` scan a specific source as a Dart file.
- */
-class ScanDartTask extends AnalysisTask {
-  /**
-   * The source to be scanned.
-   */
-  final Source source;
-
-  /**
-   * The contents of the source.
-   */
-  final String _content;
-
-  /**
-   * The token stream that was produced by scanning the source.
-   */
-  Token _tokenStream;
-
-  /**
-   * The line information that was produced.
-   */
-  LineInfo _lineInfo;
-
-  /**
-   * The errors that were produced by scanning the source.
-   */
-  List<AnalysisError> _errors = AnalysisError.NO_ERRORS;
-
-  /**
-   * Initialize a newly created task to perform analysis within the given context.
-   *
-   * @param context the context in which the task is to be performed
-   * @param source the source to be parsed
-   * @param content the contents of the source
-   */
-  ScanDartTask(InternalAnalysisContext context, this.source, this._content)
-      : super(context);
-
-  /**
-   * Return the errors that were produced by scanning the source, or `null` if the task has
-   * not yet been performed or if an exception occurred.
-   *
-   * @return the errors that were produced by scanning the source
-   */
-  List<AnalysisError> get errors => _errors;
-
-  /**
-   * Return the line information that was produced, or `null` if the task has not yet been
-   * performed or if an exception occurred.
-   *
-   * @return the line information that was produced
-   */
-  LineInfo get lineInfo => _lineInfo;
-
-  @override
-  String get taskDescription {
-    if (source == null) {
-      return "scan as dart null source";
-    }
-    return "scan as dart ${source.fullName}";
-  }
-
-  /**
-   * Return the token stream that was produced by scanning the source, or `null` if the task
-   * has not yet been performed or if an exception occurred.
-   *
-   * @return the token stream that was produced by scanning the source
-   */
-  Token get tokenStream => _tokenStream;
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => visitor.visitScanDartTask(this);
-
-  @override
-  void internalPerform() {
-    PerformanceStatistics.scan.makeCurrentWhile(() {
-      RecordingErrorListener errorListener = new RecordingErrorListener();
-      try {
-        Scanner scanner = new Scanner(
-            source, new CharSequenceReader(_content), errorListener);
-        scanner.preserveComments = context.analysisOptions.preserveComments;
-        _tokenStream = scanner.tokenize();
-        _lineInfo = new LineInfo(scanner.lineStarts);
-        _errors = errorListener.getErrorsForSource(source);
-      } catch (exception, stackTrace) {
-        throw new AnalysisException(
-            "Exception", new CaughtException(exception, stackTrace));
-      }
-    });
-  }
-}
-
-/**
- * An [AnalysisContext] that only contains sources for a Dart SDK.
- */
-class SdkAnalysisContext extends AnalysisContextImpl {
-  @override
-  AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
-    if (factory == null) {
-      return super.createCacheFromSourceFactory(factory);
-    }
-    DartSdk sdk = factory.dartSdk;
-    if (sdk == null) {
-      throw new IllegalArgumentException(
-          "The source factory for an SDK analysis context must have a DartUriResolver");
-    }
-    return new AnalysisCache(
-        <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
-  }
-}
-
-/**
- * A cache partition that contains all of the sources in the SDK.
- */
-class SdkCachePartition extends CachePartition {
-  /**
-   * Initialize a newly created partition. The [context] is the context that
-   * owns this partition. The [maxCacheSize] is the maximum number of sources
-   * for which AST structures should be kept in the cache.
-   */
-  SdkCachePartition(InternalAnalysisContext context, int maxCacheSize)
-      : super(context, maxCacheSize, DefaultRetentionPolicy.POLICY);
-
-  @override
-  bool contains(Source source) => source.isInSystemLibrary;
-}
-
-/**
- * The information cached by an analysis context about an individual source, no
- * matter what kind of source it is.
- */
-abstract class SourceEntry {
-  /**
-   * The data descriptor representing the contents of the source.
-   */
-  static final DataDescriptor<String> CONTENT =
-      new DataDescriptor<String>("SourceEntry.CONTENT");
-
-  /**
-   * The data descriptor representing the errors resulting from reading the
-   * source content.
-   */
-  static final DataDescriptor<List<AnalysisError>> CONTENT_ERRORS =
-      new DataDescriptor<List<AnalysisError>>(
-          "SourceEntry.CONTENT_ERRORS", AnalysisError.NO_ERRORS);
-
-  /**
-   * The data descriptor representing the line information.
-   */
-  static final DataDescriptor<LineInfo> LINE_INFO =
-      new DataDescriptor<LineInfo>("SourceEntry.LINE_INFO");
-
-  /**
-   * The index of the flag indicating whether the source was explicitly added to
-   * the context or whether the source was implicitly added because it was
-   * referenced by another source.
-   */
-  static int _EXPLICITLY_ADDED_FLAG = 0;
-
-  /**
-   * A table mapping data descriptors to a count of the number of times a value
-   * was set when in a given state.
-   */
-  static final Map<DataDescriptor, Map<CacheState, int>> transitionMap =
-      new HashMap<DataDescriptor, Map<CacheState, int>>();
-
-  /**
-   * The most recent time at which the state of the source matched the state
-   * represented by this entry.
-   */
-  int modificationTime = 0;
-
-  /**
-   * The exception that caused one or more values to have a state of
-   * [CacheState.ERROR].
-   */
-  CaughtException exception;
-
-  /**
-   * A bit-encoding of boolean flags associated with this element.
-   */
-  int _flags = 0;
-
-  /**
-   * A table mapping data descriptors to the cached results for those
-   * descriptors.
-   */
-  Map<DataDescriptor, CachedResult> resultMap =
-      new HashMap<DataDescriptor, CachedResult>();
-
-  /**
-   * Return all of the errors associated with this entry.
-   */
-  List<AnalysisError> get allErrors {
-    return getValue(CONTENT_ERRORS);
-  }
-
-  /**
-   * Get a list of all the library-independent descriptors for which values may
-   * be stored in this SourceEntry.
-   */
-  List<DataDescriptor> get descriptors {
-    return <DataDescriptor>[CONTENT, CONTENT_ERRORS, LINE_INFO];
-  }
-
-  /**
-   * Return `true` if the source was explicitly added to the context or `false`
-   * if the source was implicitly added because it was referenced by another
-   * source.
-   */
-  bool get explicitlyAdded => _getFlag(_EXPLICITLY_ADDED_FLAG);
-
-  /**
-   * Set whether the source was explicitly added to the context to match the
-   * [explicitlyAdded] flag.
-   */
-  void set explicitlyAdded(bool explicitlyAdded) {
-    _setFlag(_EXPLICITLY_ADDED_FLAG, explicitlyAdded);
-  }
-
-  /**
-   * Return the kind of the source, or `null` if the kind is not currently
-   * cached.
-   */
-  SourceKind get kind;
-
-  /**
-   * Fix the state of the [exception] to match the current state of the entry.
-   */
-  void fixExceptionState() {
-    if (hasErrorState()) {
-      if (exception == null) {
-        //
-        // This code should never be reached, but is a fail-safe in case an
-        // exception is not recorded when it should be.
-        //
-        String message = "State set to ERROR without setting an exception";
-        exception = new CaughtException(new AnalysisException(message), null);
-      }
-    } else {
-      exception = null;
-    }
-  }
-
-  /**
-   * Return a textual representation of the difference between the [oldEntry]
-   * and this entry. The difference is represented as a sequence of fields whose
-   * value would change if the old entry were converted into the new entry.
-   */
-  String getDiff(SourceEntry oldEntry) {
-    StringBuffer buffer = new StringBuffer();
-    _writeDiffOn(buffer, oldEntry);
-    return buffer.toString();
-  }
-
-  /**
-   * Return the state of the data represented by the given [descriptor].
-   */
-  CacheState getState(DataDescriptor descriptor) {
-    if (!_isValidDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    CachedResult result = resultMap[descriptor];
-    if (result == null) {
-      return CacheState.INVALID;
-    }
-    return result.state;
-  }
-
-  /**
-   * Return the value of the data represented by the given [descriptor], or
-   * `null` if the data represented by the descriptor is not valid.
-   */
-  /*<V>*/ dynamic /*V*/ getValue(DataDescriptor /*<V>*/ descriptor) {
-    if (!_isValidDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    CachedResult result = resultMap[descriptor];
-    if (result == null) {
-      return descriptor.defaultValue;
-    }
-    return result.value;
-  }
-
-  /**
-   * Return `true` if the state of any data value is [CacheState.ERROR].
-   */
-  bool hasErrorState() {
-    for (CachedResult result in resultMap.values) {
-      if (result.state == CacheState.ERROR) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Invalidate all of the information associated with this source.
-   */
-  void invalidateAllInformation() {
-    setState(CONTENT, CacheState.INVALID);
-    setState(CONTENT_ERRORS, CacheState.INVALID);
-    setState(LINE_INFO, CacheState.INVALID);
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to get the contents of
-   * the source represented by this entry. This will set the state of all
-   * information, including any resolution-based information, as being in error.
-   */
-  void recordContentError(CaughtException exception) {
-    setState(CONTENT, CacheState.ERROR);
-    recordScanError(exception);
-  }
-
-  /**
-   * Record that an [exception] occurred while attempting to scan or parse the
-   * entry represented by this entry. This will set the state of all
-   * information, including any resolution-based information, as being in error.
-   */
-  void recordScanError(CaughtException exception) {
-    this.exception = exception;
-    setState(LINE_INFO, CacheState.ERROR);
-  }
-
-  /**
-   * Set the state of the data represented by the given [descriptor] to the
-   * given [state].
-   */
-  void setState(DataDescriptor descriptor, CacheState state) {
-    if (!_isValidDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    if (state == CacheState.VALID) {
-      throw new ArgumentError("use setValue() to set the state to VALID");
-    }
-    _validateStateChange(descriptor, state);
-    if (state == CacheState.INVALID) {
-      resultMap.remove(descriptor);
-    } else {
-      CachedResult result =
-          resultMap.putIfAbsent(descriptor, () => new CachedResult(descriptor));
-      result.state = state;
-      if (state != CacheState.IN_PROCESS) {
-        //
-        // If the state is in-process, we can leave the current value in the
-        // cache for any 'get' methods to access.
-        //
-        result.value = descriptor.defaultValue;
-      }
-    }
-  }
-
-  /**
-   * Set the value of the data represented by the given [descriptor] to the
-   * given [value].
-   */
-  void setValue(DataDescriptor /*<V>*/ descriptor, dynamic /*V*/ value) {
-    if (!_isValidDescriptor(descriptor)) {
-      throw new ArgumentError("Invalid descriptor: $descriptor");
-    }
-    _validateStateChange(descriptor, CacheState.VALID);
-    CachedResult result =
-        resultMap.putIfAbsent(descriptor, () => new CachedResult(descriptor));
-    countTransition(descriptor, result);
-    result.state = CacheState.VALID;
-    result.value = value == null ? descriptor.defaultValue : value;
-  }
-
-  @override
-  String toString() {
-    StringBuffer buffer = new StringBuffer();
-    _writeOn(buffer);
-    return buffer.toString();
-  }
-
-  /**
-   * Flush the value of the data described by the [descriptor].
-   */
-  void _flush(DataDescriptor descriptor) {
-    CachedResult result = resultMap[descriptor];
-    if (result != null && result.state == CacheState.VALID) {
-      _validateStateChange(descriptor, CacheState.FLUSHED);
-      result.state = CacheState.FLUSHED;
-      result.value = descriptor.defaultValue;
-    }
-  }
-
-  /**
-   * Return the value of the flag with the given [index].
-   */
-  bool _getFlag(int index) => BooleanArray.get(_flags, index);
-
-  /**
-   * Return `true` if the [descriptor] is valid for this entry.
-   */
-  bool _isValidDescriptor(DataDescriptor descriptor) {
-    return descriptor == CONTENT ||
-        descriptor == CONTENT_ERRORS ||
-        descriptor == LINE_INFO;
-  }
-
-  /**
-   * Set the value of the flag with the given [index] to the given [value].
-   */
-  void _setFlag(int index, bool value) {
-    _flags = BooleanArray.set(_flags, index, value);
-  }
-
-  /**
-   * If the state of the value described by the given [descriptor] is changing
-   * from ERROR to anything else, capture the information. This is an attempt to
-   * discover the underlying cause of a long-standing bug.
-   */
-  void _validateStateChange(DataDescriptor descriptor, CacheState newState) {
-    // TODO(brianwilkerson) Decide whether we still want to capture this data.
-//    if (descriptor != CONTENT) {
-//      return;
-//    }
-//    CachedResult result = resultMap[CONTENT];
-//    if (result != null && result.state == CacheState.ERROR) {
-//      String message =
-//          "contentState changing from ${result.state} to $newState";
-//      InstrumentationBuilder builder =
-//          Instrumentation.builder2("SourceEntry-validateStateChange");
-//      builder.data3("message", message);
-//      //builder.data("source", source.getFullName());
-//      builder.record(new CaughtException(new AnalysisException(message), null));
-//      builder.log();
-//    }
-  }
-
-  /**
-   * Write a textual representation of the difference between the [oldEntry] and
-   * this entry to the given string [buffer]. Return `true` if some difference
-   * was written.
-   */
-  bool _writeDiffOn(StringBuffer buffer, SourceEntry oldEntry) {
-    bool needsSeparator = false;
-    CaughtException oldException = oldEntry.exception;
-    if (!identical(oldException, exception)) {
-      buffer.write("exception = ");
-      buffer.write(oldException.runtimeType);
-      buffer.write(" -> ");
-      buffer.write(exception.runtimeType);
-      needsSeparator = true;
-    }
-    int oldModificationTime = oldEntry.modificationTime;
-    if (oldModificationTime != modificationTime) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write("time = ");
-      buffer.write(oldModificationTime);
-      buffer.write(" -> ");
-      buffer.write(modificationTime);
-      needsSeparator = true;
-    }
-    needsSeparator =
-        _writeStateDiffOn(buffer, needsSeparator, "content", CONTENT, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "contentErrors", CONTENT_ERRORS, oldEntry);
-    needsSeparator = _writeStateDiffOn(
-        buffer, needsSeparator, "lineInfo", LINE_INFO, oldEntry);
-    return needsSeparator;
-  }
-
-  /**
-   * Write a textual representation of this entry to the given [buffer]. The
-   * result should only be used for debugging purposes.
-   */
-  void _writeOn(StringBuffer buffer) {
-    buffer.write("time = ");
-    buffer.write(modificationTime);
-    _writeStateOn(buffer, "content", CONTENT);
-    _writeStateOn(buffer, "contentErrors", CONTENT_ERRORS);
-    _writeStateOn(buffer, "lineInfo", LINE_INFO);
-  }
-
-  /**
-   * Write a textual representation of the difference between the state of the
-   * value described by the given [descriptor] between the [oldEntry] and this
-   * entry to the given [buffer]. Return `true` if some difference was written.
-   */
-  bool _writeStateDiffOn(StringBuffer buffer, bool needsSeparator, String label,
-      DataDescriptor descriptor, SourceEntry oldEntry) {
-    CacheState oldState = oldEntry.getState(descriptor);
-    CacheState newState = getState(descriptor);
-    if (oldState != newState) {
-      if (needsSeparator) {
-        buffer.write("; ");
-      }
-      buffer.write(label);
-      buffer.write(" = ");
-      buffer.write(oldState);
-      buffer.write(" -> ");
-      buffer.write(newState);
-      return true;
-    }
-    return needsSeparator;
-  }
-
-  /**
-   * Write a textual representation of the state of the value described by the
-   * given [descriptor] to the given bugger, prefixed by the given [label] to
-   * the given [buffer].
-   */
-  void _writeStateOn(
-      StringBuffer buffer, String label, DataDescriptor descriptor) {
-    CachedResult result = resultMap[descriptor];
-    buffer.write("; ");
-    buffer.write(label);
-    buffer.write(" = ");
-    buffer.write(result == null ? CacheState.INVALID : result.state);
-  }
-
-  /**
-   * Increment the count of the number of times that data represented by the
-   * given [descriptor] was transitioned from the current state (as found in the
-   * given [result] to a valid state.
-   */
-  static void countTransition(DataDescriptor descriptor, CachedResult result) {
-    Map<CacheState, int> countMap = transitionMap.putIfAbsent(
-        descriptor, () => new HashMap<CacheState, int>());
-    int count = countMap[result.state];
-    countMap[result.state] = count == null ? 1 : count + 1;
-  }
-}
-
-/**
- * The priority levels used to return sources in an optimal order. A smaller
- * ordinal value equates to a higher priority.
- */
-class SourcePriority extends Enum<SourcePriority> {
-  /**
-   * Used for a Dart source that is known to be a part contained in a library
-   * that was recently resolved. These parts are given a higher priority because
-   * there is a high probability that their AST structure is still in the cache
-   * and therefore would not need to be re-created.
-   */
-  static const SourcePriority PRIORITY_PART =
-      const SourcePriority('PRIORITY_PART', 0);
-
-  /**
-   * Used for a Dart source that is known to be a library.
-   */
-  static const SourcePriority LIBRARY = const SourcePriority('LIBRARY', 1);
-
-  /**
-   * Used for a Dart source whose kind is unknown.
-   */
-  static const SourcePriority UNKNOWN = const SourcePriority('UNKNOWN', 2);
-
-  /**
-   * Used for a Dart source that is known to be a part but whose library has not
-   * yet been resolved.
-   */
-  static const SourcePriority NORMAL_PART =
-      const SourcePriority('NORMAL_PART', 3);
-
-  /**
-   * Used for an HTML source.
-   */
-  static const SourcePriority HTML = const SourcePriority('HTML', 4);
-
-  static const List<SourcePriority> values = const [
-    PRIORITY_PART,
-    LIBRARY,
-    UNKNOWN,
-    NORMAL_PART,
-    HTML
-  ];
-
-  const SourcePriority(String name, int ordinal) : super(name, ordinal);
-}
-
-/**
  * [SourcesChangedEvent] indicates which sources have been added, removed,
  * or whose contents have changed.
  */
 class SourcesChangedEvent {
   /**
    * The internal representation of what has changed. Clients should not access
    * this field directly.
    */
   final ChangeSet _changeSet;
 
@@ skipping 58 matching lines @@
    * The data that was created from the source.
    */
   final E data;
 
   /**
    * Initialize a newly created holder to associate the given [data] with the
    * given [modificationTime].
    */
   TimestampedData(this.modificationTime, this.data);
 }
-
-/**
- * A cache partition that contains all sources not contained in other
- * partitions.
- */
-class UniversalCachePartition extends CachePartition {
-  /**
-   * Initialize a newly created partition. The [context] is the context that
-   * owns this partition. The [maxCacheSize] is the maximum number of sources
-   * for which AST structures should be kept in the cache. The [retentionPolicy]
-   * is the policy used to determine which pieces of data to remove from the
-   * cache.
-   */
-  UniversalCachePartition(InternalAnalysisContext context, int maxCacheSize,
-      CacheRetentionPolicy retentionPolicy)
-      : super(context, maxCacheSize, retentionPolicy);
-
-  @override
-  bool contains(Source source) => true;
-}
-
-/**
- * The unique instances of the class `WaitForAsyncTask` represents a state in which there is
- * no analysis work that can be done until some asynchronous task (such as IO) has completed, but
- * where analysis is not yet complete.
- */
-class WaitForAsyncTask extends AnalysisTask {
-  /**
-   * The unique instance of this class.
-   */
-  static WaitForAsyncTask _UniqueInstance = new WaitForAsyncTask();
-
-  /**
-   * Return the unique instance of this class.
-   *
-   * @return the unique instance of this class
-   */
-  static WaitForAsyncTask get instance => _UniqueInstance;
-
-  /**
-   * Prevent the creation of instances of this class.
-   */
-  WaitForAsyncTask() : super(null);
-
-  @override
-  String get taskDescription => "Waiting for async analysis";
-
-  @override
-  accept(AnalysisTaskVisitor visitor) => null;
-
-  @override
-  void internalPerform() {
-    // There is no work to be done.
-  }
-}
-
-/**
- * An object that manages a list of sources that need to have analysis work
- * performed on them.
- */
-class WorkManager {
-  /**
-   * A list containing the various queues is priority order.
-   */
-  List<List<Source>> _workQueues;
-
-  /**
-   * Initialize a newly created manager to have no work queued up.
-   */
-  WorkManager() {
-    int queueCount = SourcePriority.values.length;
-    _workQueues = new List<List<Source>>(queueCount);
-    for (int i = 0; i < queueCount; i++) {
-      _workQueues[i] = new List<Source>();
-    }
-  }
-
-  /**
-   * Record that the given [source] needs to be analyzed. The [priority] level
-   * is used to control when the source will be analyzed with respect to other
-   * sources. If the source was previously added then it's priority is updated.
-   * If it was previously added with the same priority then it's position in the
-   * queue is unchanged.
-   */
-  void add(Source source, SourcePriority priority) {
-    int queueCount = _workQueues.length;
-    int ordinal = priority.ordinal;
-    for (int i = 0; i < queueCount; i++) {
-      List<Source> queue = _workQueues[i];
-      if (i == ordinal) {
-        if (!queue.contains(source)) {
-          queue.add(source);
-        }
-      } else {
-        queue.remove(source);
-      }
-    }
-  }
-
-  /**
-   * Record that the given [source] needs to be analyzed. The [priority] level
-   * is used to control when the source will be analyzed with respect to other
-   * sources. If the source was previously added then it's priority is updated.
-   * In either case, it will be analyzed before other sources of the same
-   * priority.
-   */
-  void addFirst(Source source, SourcePriority priority) {
-    int queueCount = _workQueues.length;
-    int ordinal = priority.ordinal;
-    for (int i = 0; i < queueCount; i++) {
-      List<Source> queue = _workQueues[i];
-      if (i == ordinal) {
-        queue.remove(source);
-        queue.insert(0, source);
-      } else {
-        queue.remove(source);
-      }
-    }
-  }
-
-  /**
-   * Return an iterator that can be used to access the sources to be analyzed in
-   * the order in which they should be analyzed.
-   *
-   * <b>Note:</b> As with other iterators, no sources can be added or removed
-   * from this work manager while the iterator is being used. Unlike some
-   * implementations, however, the iterator will not detect when this
-   * requirement has been violated; it might work correctly, it might return the
-   * wrong source, or it might throw an exception.
-   */
-  WorkManager_WorkIterator iterator() => new WorkManager_WorkIterator(this);
-
-  /**
-   * Record that the given source is fully analyzed.
-   */
-  void remove(Source source) {
-    int queueCount = _workQueues.length;
-    for (int i = 0; i < queueCount; i++) {
-      _workQueues[i].remove(source);
-    }
-  }
-
-  @override
-  String toString() {
-    StringBuffer buffer = new StringBuffer();
-    List<SourcePriority> priorities = SourcePriority.values;
-    bool needsSeparator = false;
-    int queueCount = _workQueues.length;
-    for (int i = 0; i < queueCount; i++) {
-      List<Source> queue = _workQueues[i];
-      if (!queue.isEmpty) {
-        if (needsSeparator) {
-          buffer.write("; ");
-        }
-        buffer.write(priorities[i]);
-        buffer.write(": ");
-        int queueSize = queue.length;
-        for (int j = 0; j < queueSize; j++) {
-          if (j > 0) {
-            buffer.write(", ");
-          }
-          buffer.write(queue[j].fullName);
-        }
-        needsSeparator = true;
-      }
-    }
-    return buffer.toString();
-  }
-}
-
-/**
- * An iterator that returns the sources in a work manager in the order in which
- * they are to be analyzed.
- */
-class WorkManager_WorkIterator {
-  final WorkManager _manager;
-
-  /**
-   * The index of the work queue through which we are currently iterating.
-   */
-  int _queueIndex = 0;
-
-  /**
-   * The index of the next element of the work queue to be returned.
-   */
-  int _index = -1;
-
-  /**
-   * Initialize a newly created iterator to be ready to return the first element
-   * in the iteration.
-   */
-  WorkManager_WorkIterator(this._manager) {
-    _advance();
-  }
-
-  /**
-   * Return `true` if there is another [Source] available for processing.
-   */
-  bool get hasNext => _queueIndex < _manager._workQueues.length;
-
-  /**
-   * Return the next [Source] available for processing and advance so that the
-   * returned source will not be returned again.
-   */
-  Source next() {
-    if (!hasNext) {
-      throw new NoSuchElementException();
-    }
-    Source source = _manager._workQueues[_queueIndex][_index];
-    _advance();
-    return source;
-  }
-
-  /**
-   * Increment the [index] and [queueIndex] so that they are either indicating
-   * the next source to be returned or are indicating that there are no more
-   * sources to be returned.
-   */
-  void _advance() {
-    _index++;
-    if (_index >= _manager._workQueues[_queueIndex].length) {
-      _index = 0;
-      _queueIndex++;
-      while (_queueIndex < _manager._workQueues.length &&
-          _manager._workQueues[_queueIndex].isEmpty) {
-        _queueIndex++;
-      }
-    }
-  }
-}
-
-/**
- * A helper class used to create futures for AnalysisContextImpl. Using a helper
- * class allows us to preserve the generic parameter T.
- */
-class _AnalysisFutureHelper<T> {
-  final AnalysisContextImpl _context;
-
-  _AnalysisFutureHelper(this._context);
-
-  /**
-   * Return a future that will be completed with the result of calling
-   * [computeValue].  If [computeValue] returns non-null, the future will be
-   * completed immediately with the resulting value.  If it returns null, then
-   * it will be re-executed in the future, after the next time the cached
-   * information for [source] has changed.  If [computeValue] throws an
-   * exception, the future will fail with that exception.
-   *
-   * If the [computeValue] still returns null after there is no further
-   * analysis to be done for [source], then the future will be completed with
-   * the error AnalysisNotScheduledError.
-   *
-   * Since [computeValue] will be called while the state of analysis is being
-   * updated, it should be free of side effects so that it doesn't cause
-   * reentrant changes to the analysis state.
-   */
-  CancelableFuture<T> computeAsync(
-      Source source, T computeValue(SourceEntry sourceEntry)) {
-    if (_context.isDisposed) {
-      // No further analysis is expected, so return a future that completes
-      // immediately with AnalysisNotScheduledError.
-      return new CancelableFuture.error(new AnalysisNotScheduledError());
-    }
-    SourceEntry sourceEntry = _context.getReadableSourceEntryOrNull(source);
-    if (sourceEntry == null) {
-      return new CancelableFuture.error(new AnalysisNotScheduledError());
-    }
-    PendingFuture pendingFuture =
-        new PendingFuture<T>(_context, source, computeValue);
-    if (!pendingFuture.evaluate(sourceEntry)) {
-      _context._pendingFutureSources
-          .putIfAbsent(source, () => <PendingFuture>[])
-          .add(pendingFuture);
-    }
-    return pendingFuture.future;
-  }
-}