dom: more final more of the time

tools/dom/src/chrome/utils.dart

 // Copyright (c) 2013, 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.
 
 /**
  * A set of utilities for use with the Chrome Extension APIs.
  *
  * Allows for easy access to required JS objects.
  */
 part of chrome;
@@ skipping 15 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 97 matching lines @@
                                       void callback()]) =>
       JS('void',
          '#.removeRules(#, #, #)',
          this._jsObject,
          convertArgument(eventName),
          convertArgument(ruleIdentifiers),
          convertDartClosureToJS(callback, 0)
       );
 }