Disable Me2Me host controls on unsupported Linux systems.

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 288 matching lines @@
 
   // The local host cannot be stopped or started if the host controller is not
   // implemented for this platform. Additionally, it cannot be started if there
   // is an error (in many error states, the start operation will fail anyway,
   // but even if it succeeds, the chance of a related but hard-to-diagnose
   // future error is high).
   var state = this.localHostState_;
   var enabled = (state == remoting.HostController.State.STARTING) ||
       (state == remoting.HostController.State.STARTED);
   var canChangeLocalHostState =
-      (state != remoting.HostController.State.NOT_IMPLEMENTED) &&
+      (state != remoting.HostController.State.NOT_IMPLEMENTED &&
+       state != remoting.HostController.State.UNKNOWN) &&

[Sergey Ulanov, 2014/02/12 01:35:35]

This is not essential for this change, but is required to better handle corner
cases when we fail to get state of the host for some reason.

       (enabled || this.lastError_ == '');
 
   remoting.updateModalUi(enabled ? 'enabled' : 'disabled', 'data-daemon-state');
   var element = document.getElementById('daemon-control');
   element.hidden = !canChangeLocalHostState;
   element = document.getElementById('host-list-empty-hosting-supported');
   element.hidden = !canChangeLocalHostState;
   element = document.getElementById('host-list-empty-hosting-unsupported');
   element.hidden = canChangeLocalHostState;
 };
@@ skipping 190 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;