Making all callbacks use zones

tools/dom/templates/html/dartium/html_dartium.darttemplate

 // 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.
 
 // DO NOT EDIT
 // Auto-generated dart:html library.
 
 /**
  * HTML elements and other resources for web-based applications that need to
  * interact with the browser and the DOM (Document Object Model).
  *
  * This library includes DOM element types, CSS styling, local storage,
  * media, speech, events, and more.
  * To get started,
  * check out the [Element] class, the base class for many of the HTML
  * DOM types.
  *
  * ## Other resources
  *
  * * If you've never written a web app before, try our
  * tutorials—[A Game of Darts](http://dartlang.org/docs/tutorials).
- * 
+ *
  * * To see some web-based Dart apps in action and to play with the code,
  * download
  * [Dart Editor](http://www.dartlang.org/#get-started)
  * and run its built-in examples.
  *
  * * For even more examples, see
  * [Dart HTML5 Samples](https://github.com/dart-lang/dart-html5-samples)
  * on Github.
  */
 library dart.dom.html;
@@ skipping 101 matching lines @@
       _callPortLastResult = JSON.decode(_getPortSyncEventData(event));
     });
     _callPortInitialized = true;
   }
   assert(_callPortLastResult == null);
   _dispatchEvent('js-sync-message', {'id': id, 'message': message});
   var result = _callPortLastResult;
   _callPortLastResult = null;
   return result;
 }
+
+_wrapZone(callback) {
+  // For performance reasons avoid wrapping if we are in the root zone.
+  if (Zone.current == Zone.ROOT) return callback;
+  return Zone.current.bindUnaryCallback(callback, runGuarded: true);
+}