Remove generated directories with 100s of files.

client/dom/generated/src/wrapping/_NotificationCenterWrappingImplementation.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 _NotificationCenterWrappingImplementation extends DOMWrapperBase implements NotificationCenter {
-  _NotificationCenterWrappingImplementation() : super() {}
-
-  static create__NotificationCenterWrappingImplementation() native {
-    return new _NotificationCenterWrappingImplementation();
-  }
-
-  int checkPermission() {
-    return _checkPermission(this);
-  }
-  static int _checkPermission(receiver) native;
-
-  Notification createHTMLNotification(String url) {
-    return _createHTMLNotification(this, url);
-  }
-  static Notification _createHTMLNotification(receiver, url) native;
-
-  Notification createNotification(String iconUrl, String title, String body) {
-    return _createNotification(this, iconUrl, title, body);
-  }
-  static Notification _createNotification(receiver, iconUrl, title, body) native;
-
-  void requestPermission(VoidCallback callback) {
-    _requestPermission(this, callback);
-    return;
-  }
-  static void _requestPermission(receiver, callback) native;
-
-  String get typeName() { return "NotificationCenter"; }
-}