Remove support for attribute event listeners.

client/dom/generated/src/interface/Notification.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.
 
 interface Notification extends EventTarget {
 
   String get dir();
 
   void set dir(String value);
 
-  EventListener get onclick();
-
-  void set onclick(EventListener value);
-
-  EventListener get onclose();
-
-  void set onclose(EventListener value);
-
-  EventListener get ondisplay();
-
-  void set ondisplay(EventListener value);
-
-  EventListener get onerror();
-
-  void set onerror(EventListener value);
-
   String get replaceId();
 
   void set replaceId(String value);
 
   void addEventListener(String type, EventListener listener, [bool useCapture]);
 
   void cancel();
 
   bool dispatchEvent(Event evt);
 
   void removeEventListener(String type, EventListener listener, [bool useCapture]);
 
   void show();
 }