MutationObserver changes for zones (again)

tools/dom/src/shared_html.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.
 
 part of dart.dom.html;
 
 _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);
 }
 
+_wrapBinaryZone(callback) {
+  if (Zone.current == Zone.ROOT) return callback;
+  return Zone.current.bindBinaryCallback(callback, runGuarded: true);
+}
+
 Element query(String selector) => document.query(selector);
 ElementList queryAll(String selector) => document.queryAll(selector);