fix(platform-browser-dynamic): Add @Injectable() annotation to XHRImpl.

Otherwise Closure compiled code will complain that the class is missing the annootation.

modules/@angular/platform-browser-dynamic/src/xhr/xhr_impl.ts

@@ -5,12 +5,13 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-
 import {XHR} from '@angular/compiler';
+import {Injectable} from '@angular/core';
 
 import {isPresent} from '../facade/lang';
 import {PromiseCompleter, PromiseWrapper} from '../facade/promise';
 
+@Injectable()
 export class XHRImpl extends XHR {
   get(url: string): Promise<string> {
     var completer: PromiseCompleter<string> = PromiseWrapper.completer();