Remove files that have already been ported or do not need to be ported.

client/html/src/NotificationWrappingImplementation.dart

-// Copyright (c) 2011, 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(jacobr) add custom Events class.
-class NotificationWrappingImplementation extends EventTargetWrappingImplementation implements Notification {
-  NotificationWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
-
-  String get dir() { return _ptr.dir; }
-
-  void set dir(String value) { _ptr.dir = value; }
-
-  EventListener get onclick() { return LevelDom.wrapEventListener(_ptr.onclick); }
-
-  void set onclick(EventListener value) { _ptr.onclick = LevelDom.unwrap(value); }
-
-  EventListener get onclose() { return LevelDom.wrapEventListener(_ptr.onclose); }
-
-  void set onclose(EventListener value) { _ptr.onclose = LevelDom.unwrap(value); }
-
-  EventListener get ondisplay() { return LevelDom.wrapEventListener(_ptr.ondisplay); }
-
-  void set ondisplay(EventListener value) { _ptr.ondisplay = LevelDom.unwrap(value); }
-
-  EventListener get onerror() { return LevelDom.wrapEventListener(_ptr.onerror); }
-
-  void set onerror(EventListener value) { _ptr.onerror = LevelDom.unwrap(value); }
-
-  String get replaceId() { return _ptr.replaceId; }
-
-  void set replaceId(String value) { _ptr.replaceId = value; }
-
-  void cancel() {
-    _ptr.cancel();
-    return;
-  }
-
-  void show() {
-    _ptr.show();
-    return;
-  }
-
-  String get typeName() { return "Notification"; }
-}