Convert DOM and HTML frog to dart2js.

lib/html/src/frog_DOMImplementation.dart

-// 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.
-
-// TODO(vsm): Unify with Dartium version.
-class _DOMWindowCrossFrameImpl implements Window {
-  // Private window.
-  _WindowImpl _window;
-
-  // Fields.
-  // TODO(vsm): Implement history and location getters.
-
-  // TODO(vsm): Add frames to navigate subframes.  See 2312.
-
-  bool get closed() => _closed(_window);
-  static bool _closed(win) native "return win.closed;";
-
-  Window get opener() => _createSafe(_opener(_window));
-  static Window _opener(win) native "return win.opener;";
-
-  Window get parent() => _createSafe(_parent(_window));
-  static Window _parent(win) native "return win.parent;";
-
-  Window get top() => _createSafe(_top(_window));
-  static Window _top(win) native "return win.top;";
-
-  // Methods.
-  void focus() => _focus(_window);
-  static void _focus(win) native "win.focus()";
-
-  void blur() => _blur(_window);
-  static void _blur(win) native "win.blur()";
-
-  void close() => _close(_window);
-  static void _close(win) native "win.close()";
-
-  void postMessage(Dynamic message,
-                   String targetOrigin,
-                   [List messagePorts = null]) {
-    if (messagePorts == null) {
-      _postMessage2(_window, message, targetOrigin);
-    } else {
-      _postMessage3(_window, message, targetOrigin, messagePorts);
-    }
-  }
-
-  // TODO(vsm): This is a hack to workaround dartbug.com/3175.  We
-  // need a more robust convention to invoke JS methods on the
-  // underlying window.
-  static void _postMessage2(win, message, targetOrigin) native """
-    win.postMessage(message, targetOrigin);
-""";
-
-  static void _postMessage3(win, message, targetOrigin, messagePorts) native """
-    win.postMessage(message, targetOrigin, messagePorts);
-""";
-
-  // Implementation support.
-  _DOMWindowCrossFrameImpl(this._window);
-
-  static Window _createSafe(w) {
-    if (w === window) {
-      return w;
-    } else {
-      // TODO(vsm): Cache or implement equality.
-      return new _DOMWindowCrossFrameImpl(w);
-    }
-  }
-}