Remove file-level 'use strict' from file_manager.

ui/file_manager/gallery/js/background.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 {Object.<string, string>} stringData String data.
  * @param {VolumeManager} volumeManager Volume manager.
  */
 function BackgroundComponents(stringData, volumeManager) {
   /**
    * String data.
    * @type {Object.<string, string>}
    */
   this.stringData = stringData;
@@ skipping 191 matching lines @@
   chrome.runtime.onMessageExternal.addListener(function(message) {
     if (message.name !== 'testResourceLoaded')
       return;
     var script = document.createElement('script');
     script.src =
         'chrome-extension://' + window.testExtensionId +
         '/common/test_loader.js';
     document.documentElement.appendChild(script);
   });
 }