Minimal fix to get cross frame tests working, take #2.

lib/dom/templates/html/frog/html_frog.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");
 
 $!GENERATED_DART_FILES
 
 #source('../../dom/src/EventListener.dart');
 #source('../../dom/src/KeyLocation.dart');
 #source('../../dom/src/KeyName.dart');
 #source('../../dom/src/ReadyState.dart');
 #source('../../dom/src/_Collections.dart');
 #source('../../dom/src/_XMLHttpRequestUtils.dart');
 #source('../../html/src/Measurement.dart');
 #source('../../html/src/shared_FactoryProviders.dart');
+#source('../../html/src/frog_DOMImplementation.dart');
 #source('../../html/src/frog_FactoryProviders.dart');
 #source('../../html/src/frog_IDBKeyRangeFactoryProvider.dart');
 #source('../../dom/src/frog_TypedArrayFactoryProvider.dart');
 #source('../../html/src/_Testing.dart');
 #source('../../html/src/Device.dart');
 #source('../../dom/src/_ListIterators.dart');
 #source('../../dom/src/_Lists.dart');
 
 
 Window get window() native "return window;";
 _WindowImpl get _window() native "return window;";
 
 Document get document() native "return document;";
 
 _DocumentImpl get _document() native "return document;";
 
 // Workaround for tags like <cite> that lack their own Element subclass --
 // Dart issue 1990.
 class _HTMLElementImpl extends _ElementImpl native "*HTMLElement" {
 }