Added better error and OAuth support in xhr.js.

remoting/webapp/js_proto/sinon_proto.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.
 
 var sinon = sinon || {};
 
 /** @type {Object} */
 sinon.assert = {};
 
 /**
@@ skipping 109 matching lines @@
 
 /** @type {function(...):sinon.Expectation} */
 sinon.TestStub.prototype.withArgs = function() {};
 
 /** @type {function(...):sinon.Expectation} */
 sinon.TestStub.prototype.onFirstCall = function() {};
 
 /** @returns {Object}  */
 sinon.createStubInstance = function (/** * */ constructor) {};
 
-/** @return {sinon.FakeXhr} */
+/** @interface */
+sinon.FakeXhrCtrl = function() {};
+
+/**
+ * @type {?function(!sinon.FakeXhr)}
+ */
+sinon.FakeXhrCtrl.prototype.onCreate;
+
+/** @return {sinon.FakeXhrCtrl} */
 sinon.useFakeXMLHttpRequest = function() {};
 
 /** @interface */
 sinon.FakeXhr = function() {};
 
 /** @type {string} */
 sinon.FakeXhr.prototype.method;
 
 /** @type {string} */
 sinon.FakeXhr.prototype.url;
 
 /** @type {boolean} */
 sinon.FakeXhr.prototype.withCredentials;
 
 /** @type {?string} */
 sinon.FakeXhr.prototype.requestBody;
 
 /** @type {!Object<string,string>} */
 sinon.FakeXhr.prototype.requestHeaders;
 
 /**
  * @param {number} status
  * @param {!Object<string,string>} headers
  * @param {?string} content
  */
 sinon.FakeXhr.prototype.respond;
-
-/**
- * @type {?function(!sinon.FakeXhr)}
- */
-sinon.FakeXhr.prototype.onCreate;