Remove support for attribute event listeners.

client/dom/generated/src/interface/XMLHttpRequestUpload.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 XMLHttpRequestUpload extends EventTarget {
 
-  EventListener get onabort();
-
-  void set onabort(EventListener value);
-
-  EventListener get onerror();
-
-  void set onerror(EventListener value);
-
-  EventListener get onload();
-
-  void set onload(EventListener value);
-
-  EventListener get onloadstart();
-
-  void set onloadstart(EventListener value);
-
-  EventListener get onprogress();
-
-  void set onprogress(EventListener value);
-
   void addEventListener(String type, EventListener listener, [bool useCapture]);
 
   bool dispatchEvent(Event evt);
 
   void removeEventListener(String type, EventListener listener, [bool useCapture]);
 }