Move file_system libraries into 'analyzer'.

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:analyzer/file_system/file_system.dart';
 import 'package:analysis_server/src/package_map_provider.dart';
-import 'package:analysis_server/src/resource.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:watcher/watcher.dart';
 
 /**
  * Information tracked by the [ContextDirectoryManager] for each context.
  */
 class _ContextDirectoryInfo {
   /**
    * Stream subscription we are using to watch the context's directory for
@@ skipping 234 matching lines @@
    * Remove the context associated with the given [folder].
    */
   void removeContext(Folder folder);
 
   /**
    * Called when the package map for a context has changed.
    */
   void updateContextPackageMap(Folder contextFolder,
                                Map<String, List<Folder>> packageMap);
 }