One more fix for making removing overlays incremental changes.

pkg/analyzer/lib/src/context/context.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.context.context;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ skipping 952 matching lines @@
         entry.modificationTime = _contentCache.getModificationStamp(source);
         entry.setValue(CONTENT, newContents, TargetedResult.EMPTY_LIST);
       } else {
         entry.modificationTime = _contentCache.getModificationStamp(source);
       }
     } else if (originalContents != null) {
       // 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);
-        String fileContentsData = fileContents.data;
-        if (fileContentsData == originalContents) {
-          entry.setValue(CONTENT, fileContentsData, TargetedResult.EMPTY_LIST);
-          entry.modificationTime = fileContents.modificationTime;
+        newContents = fileContents.data;
+        entry.modificationTime = fileContents.modificationTime;
+        if (newContents == originalContents) {
+          entry.setValue(CONTENT, newContents, TargetedResult.EMPTY_LIST);
           changed = false;
         }
-        newContents = fileContentsData;
       } 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);
         }
       }
     }
@@ skipping 1036 matching lines @@
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
       scheduleComputation();
     }
     return pendingFuture.future;
   }
 }