Remove support for attribute event listeners.

client/dom/generated/src/interface/XMLHttpRequest.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 XMLHttpRequest extends EventTarget factory _XMLHttpRequestFactoryProvider {
 
   XMLHttpRequest();
 
 
   static final int DONE = 4;
 
   static final int HEADERS_RECEIVED = 2;
 
   static final int LOADING = 3;
 
   static final int OPENED = 1;
 
   static final int UNSENT = 0;
 
   bool get asBlob();
 
   void set asBlob(bool value);
 
-  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);
-
-  EventListener get onreadystatechange();
-
-  void set onreadystatechange(EventListener value);
-
   int get readyState();
 
   Blob get responseBlob();
 
   String get responseText();
 
   String get responseType();
 
   void set responseType(String value);
 
@@ skipping 22 matching lines @@
   void open(String method, String url, [bool async, String user, String password]);
 
   void overrideMimeType(String override);
 
   void removeEventListener(String type, EventListener listener, [bool useCapture]);
 
   void send([var data]);
 
   void setRequestHeader(String header, String value);
 }