Remove file-level 'use strict' from file_manager.

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
  */
@@ skipping 1242 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);
   }
 };