Implement automatically generated constructors for frog and dartium dart:html

client/dom/templates/html/frog/factoryprovider_XMLHttpRequest.darttemplate

+// Copyright (c) 2012, 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.
+
+class $FACTORYPROVIDER {
+  factory XMLHttpRequest() native 'return new XMLHttpRequest();';
+
+  factory XMLHttpRequest.getTEMPNAME(String url,
+                                     onSuccess(XMLHttpRequest request)) =>
+      _XMLHttpRequestUtils.getTEMPNAME(url, onSuccess);
+}