Change contract for ChangeSet to reflect AnalysisContext behavior.

pkg/analysis_server/lib/src/context_directory_manager.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 context.directory.manager;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/resource.dart';
@@ skipping 119 matching lines @@
           ChangeSet changeSet = new ChangeSet();
           changeSet.removedSource(source);
           applyChangesToContext(folder, changeSet);
           info.sources.remove(event.path);
         }
         break;
       case ChangeType.MODIFY:
         Source source = info.sources[event.path];
         if (source != null) {
           ChangeSet changeSet = new ChangeSet();
-          // TODO(paulberry): technically we should skip calling changedSource()
-          // for files that currently have their contents overridden.  However,
-          // it's hard to figure out which files have their contents overridden
-          // (this info isn't exposed through the AnalysisContext interface),
-          // and besides, if we go ahead and call changedSource() we get the
-          // behavior we want (the context continues consulting the overridden
-          // file contents).
           changeSet.changedSource(source);
           applyChangesToContext(folder, changeSet);
         }
         break;
     }
   }
 
   /**
    * Determine if the path from [folder] to [path] contains a 'packages'
    * directory.
@@ skipping 49 matching lines @@
    * some of those files have been modified).  [changeSet] is the set of
    * changes that need to be applied to the context.
    */
   void applyChangesToContext(Folder contextFolder, ChangeSet changeSet);
 
   /**
    * Remove the context associated with the given [folder].
    */
   void removeContext(Folder folder);
 }