Wrap Window in case it's a window from a different page / frame.

lib/html/scripts/systemhtml.py

 #!/usr/bin/python
 # 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.
 
 """This module provides shared functionality for the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 import os
 from generator import *
 
 _js_custom_members = set([
     'AudioBufferSourceNode.start',
     'AudioBufferSourceNode.stop',
     'CSSStyleDeclaration.setProperty',
     'Element.insertAdjacentElement',
     'Element.insertAdjacentHTML',
     'Element.insertAdjacentText',
     'Element.remove',
     'ElementEvents.mouseWheel',
     'IDBDatabase.transaction',
-    'IFrameElement.contentWindow',
     'MouseEvent.offsetX',
     'MouseEvent.offsetY',
     'SelectElement.options',
     'SelectElement.selectedOptions',
     'TableElement.createTBody',
     'LocalWindow.document',
     'LocalWindow.indexedDB',
     'LocalWindow.location',
     'LocalWindow.open',
-    'LocalWindow.top',
     'LocalWindow.webkitCancelAnimationFrame',
     'LocalWindow.webkitRequestAnimationFrame',
     ])
 
 # This map controls merging of interfaces in dart:html library.
 # All constants, attributes, and operations of merged interface (key) are
 # added to target interface (value). All references to the merged interface
 # (e.g. parameter types, return types, parent interfaces) are replaced with
 # target interface. There are two important restrictions:
 # 1) Merged and target interfaces shouldn't have common members, otherwise there
@@ skipping 1087 matching lines @@
 
     library_emitter = self._multiemitter.FileEmitter(library_file_path)
     library_file_dir = os.path.dirname(library_file_path)
     auxiliary_dir = os.path.relpath(auxiliary_dir, library_file_dir)
     imports_emitter = library_emitter.Emit(
         self._template, AUXILIARY_DIR=massage_path(auxiliary_dir))
     for path in sorted(self._path_to_emitter.keys()):
       relpath = os.path.relpath(path, library_file_dir)
       imports_emitter.Emit(
           "#source('$PATH');\n", PATH=massage_path(relpath))