Generate callbacks as typedefs.

client/dom/generated/src/wrapping/_EntryCallbackWrappingImplementation.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.
-
-// WARNING: Do not edit - generated code.
-
-class _EntryCallbackWrappingImplementation extends DOMWrapperBase implements EntryCallback {
-  _EntryCallbackWrappingImplementation() : super() {}
-
-  static create__EntryCallbackWrappingImplementation() native {
-    return new _EntryCallbackWrappingImplementation();
-  }
-
-  bool handleEvent(Entry entry) {
-    return _handleEvent(this, entry);
-  }
-  static bool _handleEvent(receiver, entry) native;
-
-  String get typeName() { return "EntryCallback"; }
-}