Update dart:chrome to include fileSystem, and update summary docs.

tools/dom/src/chrome/chrome.dart

 // Copyright (c) 2012, 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.
 
 part of chrome;
 
 // chrome.app
 class API_ChromeApp {
   /*
    * JS Variable
@@ skipping 26 matching lines @@
 class API_Chrome {
   /*
    * JS Variable
    */
   Object _jsObject;
 
   /*
    * Members
    */
   API_ChromeApp app;
+  API_file_system fileSystem;
 
   /*
    * Constructor
    */
   API_Chrome() {
     this._jsObject = JS("Object", "chrome");
     if (this._jsObject == null)
       throw new UnsupportedError('Not supported by current browser.');
 
     var app_object = JS('', '#.app', this._jsObject);
     if (app_object == null)
       throw new UnsupportedError('Not supported by current browser.');
     app = new API_ChromeApp(app_object);
+
+    var file_system_object = JS('', '#.fileSystem', this._jsObject);
+    if (file_system_object == null)
+      throw new UnsupportedError('Not supported by current browser.');
+    fileSystem = new API_file_system(file_system_object);
   }
 }
 
 // The final chrome objects
 final API_Chrome chrome = new API_Chrome();