Remove unused analysis contexts

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 'package:analysis_server/src/resource.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ skipping 62 matching lines @@
       throw new UnimplementedError(
           'Excluded paths are not supported yet');
     }
     Set<Folder> excludedFolders = new Set<Folder>();
     // diff
     Set<Folder> currentFolders = _currentDirectoryInfo.keys.toSet();
     Set<Folder> newFolders = includedFolders.difference(currentFolders);
     Set<Folder> oldFolders = currentFolders.difference(includedFolders);
     // remove old contexts
     for (Folder folder in oldFolders) {
-      // TODO(scheglov) implement
+      _currentDirectoryInfo.remove(folder);
+      removeContext(folder);
     }
     // add new contexts
     for (Folder folder in newFolders) {
       _ContextDirectoryInfo info = new _ContextDirectoryInfo();
       _currentDirectoryInfo[folder] = info;
       info.changeSubscription = folder.changes.listen((WatchEvent event) {
         _handleWatchEvent(folder, info, event);
       });
       File pubspecFile = folder.getChild('pubspec.yaml');
       addContext(folder, pubspecFile.exists ? pubspecFile : null);
@@ skipping 92 matching lines @@
    * otherwise it is null.
    */
   void addContext(Folder folder, File pubspecFile);
 
   /**
    * Called when the set of files associated with a context have changed (or
    * 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);
+}