Use WorkManager(s) in AnalysisDriver.

pkg/analyzer/lib/src/task/dart_work_manager.dart

 // Copyright (c) 2015, 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 analyzer.src.task.dart_work_manager;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 49 matching lines @@
     // part
     partSources.removeAll(changedSources);
     partSources.removeAll(removedSources);
     // unknown queue
     unknownSourceQueue.addAll(addedSources);
     unknownSourceQueue.addAll(changedSources);
     unknownSourceQueue.removeAll(removedSources);
     // library queue
     librarySourceQueue.removeAll(changedSources);
     librarySourceQueue.removeAll(removedSources);
+    // TODO(scheglov) This is an inefficient implementation.
+    // We could make the cache to return invalidated results and use them
+    // to allow work managers to schedule work request.
+    librarySourceQueue.addAll(librarySources);
   }
 
   @override
   TargetedResult getNextResult() {
     // Try to find a new library to analyze.
     while (librarySourceQueue.isNotEmpty) {
       Source librarySource = librarySourceQueue.first;
       CacheEntry entry = context.getCacheEntry(librarySource);
       CacheState state = entry.getState(LIBRARY_ERRORS_READY);
       // Maybe done with this library.
@@ skipping 17 matching lines @@
       // Compute the kind of this source.
       return new TargetedResult(source, SOURCE_KIND);
     }
     // TODO(scheglov) Report errors for parts that remained in the queue after
     // all libraries had been processed.
     // No results to compute.
     return null;
   }
 
   @override
+  WorkOrderPriority getNextResultPriority() {
+    if (unknownSourceQueue.isNotEmpty || librarySourceQueue.isNotEmpty) {
+      return WorkOrderPriority.NORMAL;
+    }
+    return WorkOrderPriority.NONE;
+  }
+
+  @override
   void resultsComputed(
       AnalysisTarget target, Map<ResultDescriptor, dynamic> outputs) {
     // Organize sources.
     if (_isDartSource(target)) {
       SourceKind kind = outputs[SOURCE_KIND];
       if (kind != null) {
         unknownSourceQueue.remove(target);
         if (kind == SourceKind.PART) {
           librarySources.remove(target);
           partSources.add(target);
         } else {
           librarySources.add(target);
           partSources.remove(target);
           librarySourceQueue.add(target);
         }
       }
     }
   }
 
   bool _isDartSource(AnalysisTarget target) {
     return target is Source && AnalysisEngine.isDartFileName(target.fullName);
   }
 }