Download the host components when user tries to enable Me2Me host.

remoting/webapp/host_list.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 representing the host-list portion of the home screen UI.
  */
 
 'use strict';
@@ skipping 62 matching lines @@
   this.lastError_ = '';
   /**
    * @type {remoting.Host?}
    * @private
    */
   this.localHost_ = null;
   /**
    * @type {remoting.HostController.State}
    * @private
    */
-  this.localHostState_ = remoting.HostController.State.NOT_IMPLEMENTED;
+  this.localHostState_ = remoting.isMe2MeSupported()
+                             ? remoting.HostController.State.NOT_INSTALLED
+                             : remoting.HostController.State.NOT_IMPLEMENTED;
   /**
    * @type {number}
    * @private
    */
   this.webappMajorVersion_ = parseInt(chrome.runtime.getManifest().version, 10);
 
   this.errorButton_.addEventListener('click',
                                      this.onErrorClick_.bind(this),
                                      false);
   var reloadButton = this.loadingIndicator_.firstElementChild;
@@ skipping 414 matching lines @@
   chrome.storage.local.set(items);
 };
 
 /**
  * Key name under which Me2Me hosts are cached.
  */
 remoting.HostList.HOSTS_KEY = 'me2me-cached-hosts';
 
 /** @type {remoting.HostList} */
 remoting.hostList = null;