Updated remoting.xhr API to use promises. Removed access to the native

remoting/webapp/base/js/spy_promise_unittest.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function() {
 
 'use strict';
 
 var originalGlobalPromise = Promise;
 
@@ skipping 230 matching lines @@
   var done = assert.async();
   var startTime = Date.now();
   var neverResolved = new base.SpyPromise(function() {});
   return base.SpyPromise.settleAll(1000).catch(function(error) {
     QUnit.ok(startTime + 1500 < Date.now());
     done();
   });
 });
 
 })();