Don't throw an exception if onfullscreenchanged fires after the plugin is

remoting/webapp/client_session.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 handling creation and teardown of a remoting client session.
  *
  * The ClientSession class controls lifetime of the client plugin
  * object and provides the plugin with the functionality it needs to
@@ skipping 1291 matching lines @@
   style.marginLeft = adjustMargin(style.marginLeft, dx,
                                   window.innerWidth, plugin.clientWidth, stopX);
 
   var stopY = { stop: false };
   style.marginTop = adjustMargin(style.marginTop, dy,
                                 window.innerHeight, plugin.clientHeight, stopY);
   return stopX.stop && stopY.stop;
 };
 
 remoting.ClientSession.prototype.resetScroll_ = function() {
-  var plugin = this.plugin_.element();
-  plugin.style.marginTop = '0px';
-  plugin.style.marginLeft = '0px';
+  if (this.plugin_) {
+    var plugin = this.plugin_.element();
+    plugin.style.marginTop = '0px';
+    plugin.style.marginLeft = '0px';
+  }
 };
 
 /**
  * Enable or disable bump-scrolling. When disabling bump scrolling, also reset
  * the scroll offsets to (0, 0).
  * @private
  * @param {boolean} enable True to enable bump-scrolling, false to disable it.
  */
 remoting.ClientSession.prototype.enableBumpScroll_ = function(enable) {
   var element = /*@type{HTMLElement} */ document.documentElement;
@@ skipping 106 matching lines @@
  * supported.
  * @private
  */
 remoting.ClientSession.prototype.createGnubbyAuthHandler_ = function() {
   if (this.mode_ == remoting.ClientSession.Mode.ME2ME) {
     this.gnubbyAuthHandler_ = new remoting.GnubbyAuthHandler(this);
     // TODO(psj): Move to more generic capabilities mechanism.
     this.sendGnubbyAuthMessage({'type': 'control', 'option': 'auth-v1'});
   }
 };