Reuse _dispatchEvent for sync message sending.

lib/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.
 
 #library("html");
 
 #import("dart:isolate");
@@ skipping 64 matching lines @@
 bool _callPortInitialized = false;
 var _callPortLastResult = null;
 
 _callPortSync(num id, var message) {
   if (!_callPortInitialized) {
     window.on['js-result'].add((event) {
       _callPortLastResult = JSON.parse(event.data);
     }, false);
     _callPortInitialized = true;
   }
-  var data = JSON.stringify({ 'id': id, 'message': message });
-  var event = document.$dom_createEvent('TextEvent');
-  event.initTextEvent('js-sync-message', false, false, window, data);
   assert(_callPortLastResult == null);
-  window.$dom_dispatchEvent(event);
+  _dispatchEvent('js-sync-message', {'id': id, 'message': message});
   var result = _callPortLastResult;
   _callPortLastResult = null;
   return result;
 }