Video Player: fix misc bugs

ui/file_manager/video_player/js/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.
  */
 
 /**
  * @param {HTMLElement} containerElement The container for the controls.
  * @param {function} onMediaError Function to display an error message.
  * @constructor
  */
 function MediaControls(containerElement, onMediaError) {
   this.container_ = containerElement;
   this.document_ = this.container_.ownerDocument;
   this.media_ = null;
 
   this.onMediaPlayBound_ = this.onMediaPlay_.bind(this, true);
   this.onMediaPauseBound_ = this.onMediaPlay_.bind(this, false);
   this.onMediaDurationBound_ = this.onMediaDuration_.bind(this);
   this.onMediaProgressBound_ = this.onMediaProgress_.bind(this);
   this.onMediaError_ = onMediaError || function() {};
+
+  this.savedVolume_ = 1;  // 100% volume.
 }
 
 /**
  * Button's state types. Values are used as CSS class names.
  * @enum {string}
  */
 MediaControls.ButtonStateType = {
   DEFAULT: 'default',
   PLAYING: 'playing',
   ENDED: 'ended'
@@ skipping 89 matching lines @@
 };
 
 /*
  * Playback control.
  */
 
 /**
  * Play the media.
  */
 MediaControls.prototype.play = function() {
+  if (!this.media_)
+    return;  // Media is detached.
+
   this.media_.play();
 };
 
 /**
  * Pause the media.
  */
 MediaControls.prototype.pause = function() {
+  if (!this.media_)
+    return;  // Media is detached.
+
   this.media_.pause();
 };
 
 /**
  * @return {boolean} True if the media is currently playing.
  */
 MediaControls.prototype.isPlaying = function() {
   return this.media_ && !this.media_.paused && !this.media_.ended;
 };
 
@@ skipping 70 matching lines @@
   var ratio = current / duration;
   this.progressSlider_.setValue(ratio);
   this.currentTime_.textContent = MediaControls.formatTime_(current);
 };
 
 /**
  * @param {number} value Progress [0..1].
  * @private
  */
 MediaControls.prototype.onProgressChange_ = function(value) {
+  if (!this.media_)
+    return;  // Media is detached.
+
   if (!this.media_.seekable || !this.media_.duration) {
     console.error('Inconsistent media state');
     return;
   }
 
   var current = this.media_.duration * value;
   this.media_.currentTime = current;
   this.currentTime_.textContent = MediaControls.formatTime_(current);
 };
 
 /**
  * @param {boolean} on True if dragging.
  * @private
  */
 MediaControls.prototype.onProgressDrag_ = function(on) {
   if (!this.media_)
-    return;
+    return;  // Media is detached.
 
   if (on) {
     this.resumeAfterDrag_ = this.isPlaying();
     this.media_.pause();
   } else {
     if (this.resumeAfterDrag_) {
       if (this.media_.ended)
         this.onMediaPlay_(false);
       else
         this.media_.play();
@@ skipping 48 matching lines @@
   if (value <= 1 / 3) return 1;
   if (value <= 2 / 3) return 2;
   return 3;
 };
 
 /**
  * @param {number} value Volume [0..1].
  * @private
  */
 MediaControls.prototype.onVolumeChange_ = function(value) {
+  if (!this.media_)
+    return;  // Media is detached.
+
   this.media_.volume = value;
   this.soundButton_.setAttribute('level', MediaControls.getVolumeLevel_(value));
 };
 
 /**
  * @param {boolean} on True if dragging is in progress.
  * @private
  */
 MediaControls.prototype.onVolumeDrag_ = function(on) {
   if (on && (this.media_.volume != 0)) {
@@ skipping 18 matching lines @@
   this.media_.addEventListener('durationchange', this.onMediaDurationBound_);
   this.media_.addEventListener('timeupdate', this.onMediaProgressBound_);
   this.media_.addEventListener('error', this.onMediaError_);
 
   // Reflect the media state in the UI.
   this.onMediaDuration_();
   this.onMediaPlay_(this.isPlaying());
   this.onMediaProgress_();
   if (this.volume_) {
     /* Copy the user selected volume to the new media element. */
-    this.media_.volume = this.volume_.getValue();
+    this.savedVolume_ = this.media_.volume = this.volume_.getValue();
   }
 };
 
 /**
  * Detach media event handlers.
  */
 MediaControls.prototype.detachMedia = function() {
   if (!this.media_)
     return;
 
@@ skipping 45 matching lines @@
 
   this.enableControls_('.media-control', true);
 
   var sliderContainer = this.progressSlider_.getContainer();
   if (this.media_.seekable)
     sliderContainer.classList.remove('readonly');
   else
     sliderContainer.classList.add('readonly');
 
   var valueToString = function(value) {
+    var duration = this.media_ ? this.media_.duration : 0;
     return MediaControls.formatTime_(this.media_.duration * value);
   }.bind(this);
 
   this.duration_.textContent = valueToString(1);
 
   if (this.progressSlider_.setValueToStringFunction)
     this.progressSlider_.setValueToStringFunction(valueToString);
 
   if (this.media_.seekable)
     this.restorePlayState();
@@ skipping 780 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);
   }
 };