Show a helpful error message if a host domain policy blocked an attempt to use

remoting/webapp/host_session.js

 // Copyright (c) 2012 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.
 
 /**
  * @fileoverview
  * Class handling creation and teardown of a remoting host session.
  *
  * This abstracts a <embed> element and controls the plugin which does the
  * actual remoting work.  There should be no UI code inside this class.  It
@@ skipping 18 matching lines @@
 // must be kept in sync.
 /** @enum {number} */
 remoting.HostSession.State = {
   UNKNOWN: -1,
   DISCONNECTED: 0,
   STARTING: 1,
   REQUESTED_ACCESS_CODE: 2,
   RECEIVED_ACCESS_CODE: 3,
   CONNECTED: 4,
   DISCONNECTING: 5,
-  ERROR: 6
+  ERROR: 6,
+  INVALID_DOMAIN_ERROR: 7
 };
 
 /**
  * Create an instance of the host plugin.
  * @return {remoting.HostPlugin} The new plugin instance.
  */
 remoting.HostSession.createPlugin = function() {
   var plugin = document.createElement('embed');
   plugin.type = remoting.PLUGIN_MIMETYPE;
   // Hiding the plugin means it doesn't load, so make it size zero instead.
@@ skipping 62 matching lines @@
 };
 
 
 /**
  * Remove the plugin element from the document.
  * @return {void} Nothing.
  */
 remoting.HostSession.prototype.removePlugin = function() {
   this.plugin.parentNode.removeChild(this.plugin);
 };