Remove 'Enable' button on unsupported platforms. Added 'No hosts' message.

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';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * Create a host list consisting of the specified HTML elements, which should
  * have a common parent that contains only host-list UI as it will be hidden
  * if the host-list is empty.
  *
  * @constructor
- * @param {Element} table The HTML <table> to contain host-list.
+ * @param {Element} table The HTML <div> to contain host-list.
+ * @param {Element} noHosts The HTML <div> containing the "no hosts" message.
  * @param {Element} errorMsg The HTML <div> to display error messages.
  * @param {Element} errorButton The HTML <button> to display the error
  *     resolution action.
  */
-remoting.HostList = function(table, errorMsg, errorButton) {
+remoting.HostList = function(table, noHosts, errorMsg, errorButton) {
   /**
    * @type {Element}
    * @private
    */
   this.table_ = table;
   /**
    * @type {Element}
    * @private
+   * TODO(jamiewalch): This should be doable using CSS's sibling selector,
+   * but it doesn't work right now (crbug.com/135050).
+   */
+  this.noHosts_ = noHosts;
+  /**
+   * @type {Element}
+   * @private
    */
   this.errorMsg_ = errorMsg;
   /**
    * @type {Element}
    * @private
    */
   this.errorButton_ = errorButton;
   /**
    * @type {Array.<remoting.HostTableEntry>}
    * @private
@@ skipping 133 matching lines @@
  * Display the list of hosts or error condition.
  *
  * @param {string?} thisHostId The id of this host, or null if not registered.
  * @return {void} Nothing.
  */
 remoting.HostList.prototype.display = function(thisHostId) {
   this.table_.innerText = '';
   this.errorMsg_.innerText = '';
   this.hostTableEntries_ = [];
 
-  this.table_.hidden = (this.hosts_.length == 0);
+  var noHostsRegistered = (this.hosts_.length == 0);
+  this.table_.hidden = noHostsRegistered;
+  this.noHosts_.hidden = !noHostsRegistered;
 
   for (var i = 0; i < this.hosts_.length; ++i) {
     /** @type {remoting.Host} */
     var host = this.hosts_[i];
     // Validate the entry to make sure it has all the fields we expect and is
     // not the local host (which is displayed separately). NB: if the host has
     // never sent a heartbeat, then there will be no jabberId.
     if (host.hostName && host.hostId && host.status && host.publicKey &&
         host.hostId != thisHostId) {
       var hostTableEntry = new remoting.HostTableEntry();
@@ skipping 118 matching lines @@
   }
 }
 
 /**
  * Key name under which Me2Me hosts are cached.
  */
 remoting.HostList.HOSTS_KEY = 'me2me-cached-hosts';
 
 /** @type {remoting.HostList} */
 remoting.hostList = null;