Partially fix the cache invalidation problem during incremental resolution.

pkg/analyzer/lib/src/generated/incremental_resolver.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.incremental_resolver;
 
 import 'dart:collection';
 import 'dart:math' as math;
 
 import 'package:analyzer/src/context/cache.dart'
@@ skipping 846 matching lines @@
   @override
   DeltaResult validate(InternalAnalysisContext context, AnalysisTarget target,
       ResultDescriptor descriptor) {
     // don't invalidate results of standard Dart tasks
     bool isByTask(TaskDescriptor taskDescriptor) {
       return taskDescriptor.results.contains(descriptor);
     }
     if (descriptor == CONTENT) {
       return DeltaResult.KEEP_CONTINUE;
     }
+    if (target is Source && target != source) {
+      if (isByTask(DartErrorsTask.DESCRIPTOR) ||
+          isByTask(LibraryErrorsReadyTask.DESCRIPTOR)) {
+        return DeltaResult.KEEP_CONTINUE;
+      }
+    }
+    if (target is LibrarySpecificUnit &&
+        target.unit != source &&
+        target.library != source) {
+      if (isByTask(GatherUsedLocalElementsTask.DESCRIPTOR) ||
+          isByTask(GatherUsedImportedElementsTask.DESCRIPTOR) ||
+          isByTask(GenerateHintsTask.DESCRIPTOR) ||
+          isByTask(LibraryUnitErrorsTask.DESCRIPTOR)) {
+        return DeltaResult.KEEP_CONTINUE;
+      }
+    }
     if (isByTask(BuildCompilationUnitElementTask.DESCRIPTOR) ||
         isByTask(BuildDirectiveElementsTask.DESCRIPTOR) ||
         isByTask(BuildEnumMemberElementsTask.DESCRIPTOR) ||
         isByTask(BuildExportNamespaceTask.DESCRIPTOR) ||
         isByTask(BuildLibraryElementTask.DESCRIPTOR) ||
         isByTask(BuildPublicNamespaceTask.DESCRIPTOR) ||
         isByTask(BuildSourceExportClosureTask.DESCRIPTOR) ||
         isByTask(BuildSourceImportExportClosureTask.DESCRIPTOR) ||
         isByTask(ComputeConstantDependenciesTask.DESCRIPTOR) ||
         isByTask(ComputeConstantValueTask.DESCRIPTOR) ||
@@ skipping 367 matching lines @@
   }
 
   void _shiftErrors_OLD(DataDescriptor<List<AnalysisError>> descriptor) {
     List<AnalysisError> errors =
         oldEntry.getValueInLibrary(descriptor, _librarySource);
     _shiftErrors(errors);
   }
 
   void _updateCache() {
     if (newSourceEntry != null) {
-      newSourceEntry.setState(CONTENT, CacheState.INVALID,
-          delta: new IncrementalBodyDelta(_source, _updateOffset, _updateEndOld,
-              _updateEndNew, _updateDelta));
+      LoggingTimer timer = logger.startTimer();
+      try {
+        newSourceEntry.setState(CONTENT, CacheState.INVALID,
+            delta: new IncrementalBodyDelta(_source, _updateOffset,
+                _updateEndOld, _updateEndNew, _updateDelta));
+      } finally {
+        timer.stop('invalidate cache with delta');
+      }
     }
   }
 
   void _updateElementNameOffsets() {
     LoggingTimer timer = logger.startTimer();
     try {
       _definingUnit
           .accept(new _ElementNameOffsetUpdater(_updateOffset, _updateDelta));
     } finally {
       timer.stop('update element offsets');
@@ skipping 853 matching lines @@
   @override
   String toString() => name;
 }
 
 class _TokenPair {
   final _TokenDifferenceKind kind;
   final Token oldToken;
   final Token newToken;
   _TokenPair(this.kind, this.oldToken, this.newToken);
 }