Use @Native annotation on dart2js DOM native classes

tools/dom/templates/html/impl/impl_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.
 
 part of $LIBRARYNAME;
 
  /**
   * A client-side XHR request for getting data from a URL,
   * formally known as XMLHttpRequest.
   *
@@ skipping 33 matching lines @@
   * * [Fetch Data Dynamically](https://www.dartlang.org/docs/tutorials/fetchdata/),
   * a tutorial from _A Game of Darts_,
   * shows two different ways to use HttpRequest to get a JSON file.
   * * [Get Input from a Form](https://www.dartlang.org/docs/tutorials/forms/),
   * another tutorial from _A Game of Darts_,
   * shows using HttpRequest with a custom server.
   * * [Dart article on using HttpRequests](http://www.dartlang.org/articles/json-web-service/#getting-data)
   * * [JS XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest)
   * * [Using XMLHttpRequest](https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest/Using_XMLHttpRequest)
  */
-$(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
+$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 
   /**
    * Creates a GET request for the specified [url].
    *
    * The server response must be a `text/` mime type for this request to
    * succeed.
    *
    * This is similar to [request] but specialized for HTTP GET requests which
    * return text content.
    *
@@ skipping 306 matching lines @@
         headers[key] = '${headers[key]}, $value';
       } else {
         headers[key] = value;
       }
     }
     return headers;
   }
 
 $!MEMBERS
 }