Fix null pointer error.

remoting/webapp/me2mom/toolbar.js

 // Copyright (c) 2011 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';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * @param {Element} toolbar The HTML element representing the tool-bar.
  * @constructor
  */
 remoting.Toolbar = function(toolbar) {
   /**
    * @type {Element}
    * @private
    */
   this.toolbar_ = toolbar;
+  /**
+   * @type {boolean} False if the tool-bar is currently hidden, or should be
+   *      hidden once the over-shoot timer expires; true otherwise.
+   */
+  this.visible = false;
+  /**
+   * @type {number?} The id of the current timer, if any.
+   */
+  this.timerId = null;
+
   /** @type {remoting.Toolbar} */
   var that = this;
 
   /**
    * @param {Event} event The mouseout event, used to determine whether or
    *     not the mouse is leaving the tool-bar or (due to event-bubbling)
    *     one of its children.
    */
   var onMouseOut = function(event) {
     for (var e = event.toElement; e != null; e = e.parentElement) {
       if (e == that.toolbar_) {
         return;  // Still over a child element => ignore.
       }
     }
     that.hide_();
   };
   this.toolbar_.onmouseout = onMouseOut;
 
   this.toolbar_.onmouseover = function() {
     that.showForAtLeast_(1000);
   };
 
-  /**
-   * @type {boolean} False if the tool-bar is currently hidden, or should be
-   *      hidden once the over-shoot timer expires; true otherwise.
-   */
-  this.visible = false;
-  /**
-   * @type {number?} The id of the current timer, if any.
-   */
-  this.timerId = null;
+  window.addEventListener('resize', function() { that.center(); }, false);
 };
 
 /**
  * Preview the tool-bar functionality by showing it for 3s if it is not
  *     already visible.
  * @return {void} Nothing.
  */
 remoting.Toolbar.prototype.preview = function() {
   this.showForAtLeast_(3000);
   this.visible = false;
@@ skipping 62 matching lines @@
   if (!this.visible) {
     removeClass(this.toolbar_, remoting.Toolbar.VISIBLE_CLASS_);
   }
 };
 
 /** @type {remoting.Toolbar} */
 remoting.toolbar = null;
 
 /** @private */
 remoting.Toolbar.VISIBLE_CLASS_ = 'toolbar-visible';