[Chromoting] Show any startup errors in the LoadingWindow.

remoting/webapp/base/js/typecheck.js

 // Copyright 2014 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.
 
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 (function() {
 'use strict';
 
 /**
  * @param {*} value
  * @return {boolean}
  */
 var isArray = function(value) {
   return Array.isArray(value);
 };
 
 /**
  * @param {*} value
+ * @param {boolean=} opt_allowUndefined True to accept undefined.
  * @return {boolean}
  */
-var isBoolean = function(value) {
+var isBoolean = function(value, opt_allowUndefined) {
+  if (opt_allowUndefined && value === 'undefined') {
+    return true;
+  }
   return typeof value == 'boolean';
 };
 
 /**
  * @param {*} value
+ * @param {boolean=} opt_allowUndefined True to accept undefined.
  * @return {boolean}
  */
-var isNumber = function(value) {
+var isNumber = function(value, opt_allowUndefined) {
+  if (opt_allowUndefined && value === 'undefined') {
+    return true;
+  }
   return typeof value == 'number';
 };
 
 /**
  * @param {*} value
  * @return {boolean}
  */
 var isObject = function(value) {
   return value != null && typeof value == 'object' && !Array.isArray(value);
 };
 
 /**
  * @param {*} value
+ * @param {boolean=} opt_allowUndefined True to accept undefined.
  * @return {boolean}
  */
-var isString = function(value) {
+var isString = function(value, opt_allowUndefined) {
+  if (opt_allowUndefined && value === 'undefined') {
+    return true;
+  }
   return typeof value == 'string';
 };
 
 /**
  * @param {*} value
  * @return {string}
  */
 var jsonTypeOf = function(value) {
   if (typeof value == 'object') {
     if (value === null) {
@@ skipping 180 matching lines @@
  * If the string cannot be parsed, or does not result in an object, then an
  * exception will be thrown.
  *
  * @param {string} jsonString The JSON string to parse.
  * @return {Object} The JSON object created from the |jsonString|.
  */
 base.getJsonObjectFromString = function(jsonString) {
   return base.assertObject(base.jsonParseSafe(jsonString));
 };
 
-})();
+})();