Support DOMString[] and regenerate from IDL

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();
 
@@ skipping 61 matching lines @@
   void abort();
 
   void addEventListener(String type, EventListener listener, [bool useCapture]);
 
   bool dispatchEvent(Event evt);
 
   String getAllResponseHeaders();
 
   String getResponseHeader(String header);
 
-  void open(String method, String url, bool async, [String user, String password]);
+  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);
 }