dom: more final more of the time

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
    */
-  Object _jsObject;
+  final Object _jsObject;
 
   /*
    * Members
    */
   API_app_window window;
   API_app_runtime runtime;
 
   /*
    * Constructor
    */
@@ skipping 32 matching lines @@
 
     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);
   }
 }
 
 // The final chrome objects
 final API_Chrome chrome = new API_Chrome();