[VideoPlayer] dedicated video player app

chrome/browser/resources/file_manager/foreground/js/media/media_controls.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.
 
 'use strict';
 
 /**
  * @fileoverview MediaControls class implements media playback controls
  * that exist outside of the audio/video HTML element.
  */
@@ skipping 472 matching lines @@
  */
 MediaControls.prototype.restorePlayState = function() {};
 
 /**
  * Encode current state into the page URL or the app state.
  */
 MediaControls.prototype.encodeState = function() {
   if (!this.media_.duration)
     return;
 
-  window.appState.time = this.media_.currentTime;
-  util.saveAppState();
+  if (window.appState) {
+    window.appState.time = this.media_.currentTime;
+    util.saveAppState();
+  }
   return;
 };
 
 /**
  * Decode current state from the page URL or the app state.
  * @return {boolean} True if decode succeeded.
  */
 MediaControls.prototype.decodeState = function() {
-  if (!('time' in window.appState))
+  if (!window.appState || !('time' in window.appState))
     return false;
   // There is no page reload for apps v2, only app restart.
   // Always restart in paused state.
-  this.media_.currentTime = appState.time;
+  this.media_.currentTime = window.appState.time;
   this.pause();
   return true;
 };
 
 /**
  * Remove current state from the page URL or the app state.
  */
 MediaControls.prototype.clearState = function() {
+  if (!window.appState)
+    return;
+
   if ('time' in window.appState)
     delete window.appState.time;
   util.saveAppState();
   return;
 };
 
 /**
  * Create a customized slider control.
  *
  * @param {HTMLElement} container The containing div element.
@@ skipping 668 matching lines @@
 AudioControls.prototype.onAdvanceClick_ = function(forward) {
   if (!forward &&
       (this.getMedia().currentTime > AudioControls.TRACK_RESTART_THRESHOLD)) {
     // We are far enough from the beginning of the current track.
     // Restart it instead of than skipping to the previous one.
     this.getMedia().currentTime = 0;
   } else {
     this.advanceTrack_(forward);
   }
 };