dom: more final more of the time

sdk/lib/chrome/dart2js/chrome_dart2js.dart

 /// Native wrappers for the Chrome Packaged App APIs.
 ///
 /// These functions allow direct access to the Packaged App APIs, allowing
 /// Chrome Packaged Apps to be written using Dart.
 ///
 /// For more information on these APIs, see the
 /// [Chrome APIs Documentation](http://developer.chrome.com/extensions/api_index.html)
 library chrome;
 
 import 'dart:_foreign_helper' show JS;
@@ skipping 41 matching lines @@
   /*
    * Internal proxy constructor
    *
    * Creates a new Dart object using this existing proxy.
    */
   ChromeObject._proxy(this._jsObject);
 
   /*
    * JS Object Representation
    */
-  Object _jsObject;
+  final Object _jsObject;
 }
 
 /**
  * Useful functions for converting arguments.
  */
 
 /**
  * Converts the given map-type argument to js-friendly format, recursively.
  * Returns the new Map object.
  */
@@ skipping 116 matching lines @@
  *        => super.removeListener(callback);
  *    bool hasListener(void callback(LaunchData launchData))
  *        => super.hasListener(callback);
  *  }
  *
  */
 class Event {
   /*
    * JS Object Representation
    */
-  Object _jsObject;
+  final Object _jsObject;
 
   /*
    * Number of arguments the callback takes.
    */
-  int _callbackArity;
+  final int _callbackArity;
 
   /*
    * Private constructor
    */
   Event._(this._jsObject, this._callbackArity);
 
   /*
    * Methods
    */
 
@@ skipping 107 matching lines @@
 // 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.
 
 
 // chrome.app
 class API_ChromeApp {
   /*
    * JS Variable
    */
-  Object _jsObject;
+  final Object _jsObject;
 
   /*
    * Members
    */
   API_app_window window;
   API_app_runtime runtime;
 
   /*
    * Constructor
    */
@@ skipping 773 matching lines @@
   /// postIntentResponse is an internal method to responds to an intent
   /// previously sent to a packaged app. This is identified by intentId, and
   /// should only be invoked at most once per intentId.
   void postIntentResponse(AppRuntimeIntentResponse intentResponse) => JS('void', '#.postIntentResponse(#)', this._jsObject, convertArgument(intentResponse));
 
   API_app_runtime(this._jsObject) {
     onLaunched = new Event_app_runtime_onLaunched(JS('', '#.onLaunched', this._jsObject));
     onRestarted = new Event_app_runtime_onRestarted(JS('', '#.onRestarted', this._jsObject));
   }
 }