Fix remoting.Toolbar.setClientSession() to handle clientSession=null.

remoting/webapp/toolbar.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 client tool-bar.
  */
 
 'use strict';
@@ skipping 103 matching lines @@
   this.toolbar_.classList.toggle(remoting.Toolbar.VISIBLE_CLASS_);
 };
 
 /**
  * @param {remoting.ClientSession} clientSession The active session, or null if
  *     there is no connection.
  */
 remoting.Toolbar.prototype.setClientSession = function(clientSession) {
   this.optionsMenu_.setClientSession(clientSession);
   var connectedTo = document.getElementById('connected-to');
-  connectedTo.innerText = clientSession.getHostDisplayName();
+  connectedTo.innerText =
+      clientSession ? clientSession.getHostDisplayName() : "";
 };
 
 /**
  * Test the specified co-ordinate to see if it is close enough to the stub
  * to activate it.
  *
  * @param {number} x The x co-ordinate.
  * @param {number} y The y co-ordinate.
  * @return {boolean} True if the position should activate the tool-bar stub, or
  *     false otherwise.
@@ skipping 28 matching lines @@
   }
 };
 
 /** @type {remoting.Toolbar} */
 remoting.toolbar = null;
 
 /** @private */
 remoting.Toolbar.STUB_EXTENDED_CLASS_ = 'toolbar-stub-extended';
 /** @private */
 remoting.Toolbar.VISIBLE_CLASS_ = 'toolbar-visible';