Add DirectoryBasedDartSdk.useSummary property.

pkg/analyzer/lib/src/generated/sdk_io.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 analyzer.src.generated.sdk_io;
 
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 189 matching lines @@
    * The directory containing the SDK.
    */
   JavaFile _sdkDirectory;
 
   /**
    * The directory within the SDK directory that contains the libraries.
    */
   JavaFile _libraryDirectory;
 
   /**
+   * The flag that specifies whether SDK summary should be used.
+   */
+  bool _useSummary = false;

[Brian Wilkerson, 2016/02/09 20:41:07]

I don't understand what the value of this flag is or where this code is going
long term. Currently this field is initialized to `false` and explicitly set to
`false` in one place, so it can never be `true`. Will the default change? Will
other clients set it to `true`?

+
+  /**
    * The revision number of this SDK, or `"0"` if the revision number cannot be
    * discovered.
    */
   String _sdkVersion;
 
   /**
    * The file containing the dart2js executable.
    */
   JavaFile _dart2jsExecutable;
 
@@ skipping 32 matching lines @@
     _libraryMap = initialLibraryMap(useDart2jsPaths);
   }
 
   @override
   AnalysisContext get context {
     if (_analysisContext == null) {
       _analysisContext = new SdkAnalysisContext();
       SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
       _analysisContext.sourceFactory = factory;
       // Try to use summaries.
-      SdkBundle sdkBundle = _getSummarySdkBundle();
-      if (sdkBundle != null) {
-        _analysisContext.resultProvider =
-            new SdkSummaryResultProvider(_analysisContext, sdkBundle);
+      if (_useSummary) {
+        SdkBundle sdkBundle = _getSummarySdkBundle();
+        if (sdkBundle != null) {
+          _analysisContext.resultProvider =
+              new SdkSummaryResultProvider(_analysisContext, sdkBundle);
+        }
       }
     }
     return _analysisContext;
   }
 
   /**
    * Return the file containing the dart2js executable, or `null` if it does not
    * exist.
    */
   JavaFile get dart2JsExecutable {
@@ skipping 107 matching lines @@
         // Fall through to return the default.
       }
     }
     return _sdkVersion;
   }
 
   @override
   List<String> get uris => _libraryMap.uris;
 
   /**
+   * Specify whether SDK summary should be used.  This property can only be set
+   * before [context] was invoked.

[Paul Berry, 2016/02/09 20:36:08]

s/was/is/

+   */
+  void set useSummary(bool use) {
+    if (_analysisContext != null) {
+      throw new StateError('SDK analysis context has been already created.');
+    }
+    _useSummary = use;
+  }
+
+  /**
    * Return the name of the file containing the VM executable.
    */
   String get vmBinaryName {
     if (OSUtilities.isWindows()) {
       return _VM_EXECUTABLE_NAME_WIN;
     } else {
       return _VM_EXECUTABLE_NAME;
     }
   }
 
@@ skipping 241 matching lines @@
     SdkLibrariesReader_LibraryBuilder libraryBuilder =
         new SdkLibrariesReader_LibraryBuilder(_useDart2jsPaths);
     // If any syntactic errors were found then don't try to visit the AST
     // structure.
     if (!errorListener.errorReported) {
       unit.accept(libraryBuilder);
     }
     return libraryBuilder.librariesMap;
   }
 }