Video Player: Keep the display awake during playing a video

ui/file_manager/video_player/js/video_player.js

 // Copyright 2014 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';
 
 /**
  * @param {Element} playerContainer Main container.
  * @param {Element} videoContainer Container for the video element.
  * @param {Element} controlsContainer Container for video controls.
@@ skipping 246 matching lines @@
       loadTimeData.getString('VIDEO_PLAYER_PLAY_ON'));
 
   document.addEventListener('keydown', reloadVideo);
   document.addEventListener('click', reloadVideo);
 };
 
 /**
  * Unloads the player.
  */
 function unload() {
+  // Releases keep awake just in case (should be released on unloading video).
+  chrome.power.releaseKeepAwake();
+
   if (!player.controls || !player.controls.getMedia())
     return;
 
   player.controls.savePosition(true /* exiting */);
   player.controls.cleanup();
 }
 
 /**
  * Loads the video file.
  * @param {Object} video Data of the video file.
@@ skipping 96 matching lines @@
               if (opt_callback)
                 opt_callback();
               videoPlayerElement.removeAttribute('loading');
               this.controls.inactivityWatcher.disabled = false;
             }
 
             this.videoElement_.removeEventListener('loadedmetadata', handler);
           }.wrap(this, this.currentPos_);
 
           this.videoElement_.addEventListener('loadedmetadata', handler);
+
+          this.videoElement_.addEventListener('play', function() {
+            chrome.power.requestKeepAwake('display');
+          }.wrap());
+          this.videoElement_.addEventListener('pause', function() {
+            chrome.power.releaseKeepAwake();
+          }.wrap());
+
           this.videoElement_.load();
           callback();
         }.bind(this)).
         // In case of error.
         catch(function(error) {
           videoPlayerElement.removeAttribute('loading');
           console.error('Failed to initialize the video element.',
                         error.stack || error);
           this.controls_.showErrorMessage('GALLERY_VIDEO_ERROR');
           callback();
         }.bind(this));
   }.wrap(this));
 };
 
 /**
  * Plays the first video.
  */
 VideoPlayer.prototype.playFirstVideo = function() {
   this.currentPos_ = 0;
   this.reloadCurrentVideo(this.onFirstVideoReady_.wrap(this));
 };
 
 /**
  * Unloads the current video.
  * @param {boolean=} opt_keepSession If true, keep using the current session.
  *     Otherwise, discards the session.
  */
 VideoPlayer.prototype.unloadVideo = function(opt_keepSession) {
   this.loadQueue_.run(function(callback) {
+    chrome.power.releaseKeepAwake();
+
     if (this.videoElement_) {
       // If the element has dispose method, call it (CastVideoElement has it).
       if (this.videoElement_.dispose)
         this.videoElement_.dispose();
       // Detach the previous video element, if exists.
       if (this.videoElement_.parentNode)
         this.videoElement_.parentNode.removeChild(this.videoElement_);
     }
     this.videoElement_ = null;
 
@@ skipping 225 matching lines @@
 var initPromise = Promise.all(
     [new Promise(initVideos.wrap(null)),
      new Promise(initStrings.wrap(null)),
      new Promise(util.addPageLoadHandler.wrap(null))]);
 
 initPromise.then(function(results) {
   var videos = results[0];
   player.prepare(videos);
   return new Promise(player.playFirstVideo.wrap(player));
 }.wrap(null));