Video Player: Support seek on casting

ui/file_manager/video_player/js/cast/cast_video_element.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';
 
 /**
  * Interval for updating media info (in ms).
  * @type {number}
  * @const
@@ skipping 73 matching lines @@
     if (this.castMedia_) {
       if (this.castMedia_.idleReason === chrome.cast.media.IdleReason.FINISHED)
         return this.currentMediaDuration_;  // Returns the duration.
       else
         return this.castMedia_.getEstimatedTime();
     } else {
       return null;
     }
   },
   set currentTime(currentTime) {
-    // TODO(yoshiki): Support seek.
+    var seekRequest = new chrome.cast.media.SeekRequest();
+    seekRequest.currentTime = currentTime;
+    this.castMedia_.seek(seekRequest,
+        function() {},
+        this.onCastCommandError_.wrap(this));
   },
 
   /**
    * If this video is pauses or not.
    * @type {boolean}
    */
   get paused() {
     if (!this.castMedia_)
       return false;
 
     return !this.playInProgress_ &&
         (this.pauseInProgress_ ||
          this.castMedia_.playerState === chrome.cast.media.PlayerState.PAUSED);
   },
 
   /**
    * If this video is ended or not.
    * @type {boolean}
    */
   get ended() {
     if (!this.castMedia_)
       return true;
 
    return this.castMedia_.idleReason === chrome.cast.media.IdleReason.FINISHED;
   },
 
   /**
-   * If this video is seekable or not.
-   * @type {boolean}
+   * TimeRange object that represents the seekable ranges of the media
+   * resource.
+   * @type {TimeRanges}
    */
   get seekable() {
-    // TODO(yoshiki): Support seek.
-    return false;
+    return {
+      length: 1,
+      start: function(index) { return 0; },
+      end: function(index) { return this.currentMediaDuration_; },
+    };
   },
 
   /**
    * Value of the volume
    * @type {number}
    */
   get volume() {
     return this.castSession_.receiver.volume.muted ?
                0 :
                this.castSession_.receiver.volume.level;
@@ skipping 269 matching lines @@
       this.dispatchEvent(new Event('durationchange'));
     }
 
     // Media is being unloaded.
     if (!alive) {
       this.unloadMedia_();
       return;
     }
   },
 };