Remove file-level 'use strict' from file_manager.

ui/file_manager/image_loader/scheduler.js

 // Copyright 2013 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';
-
 /**
  * Scheduler for requests. Fetches requests from a queue and processes them
  * synchronously, taking into account priorities. The highest priority is 0.
  * @constructor
  */
 function Scheduler() {
   /**
    * List of requests waiting to be checked. If these items are available in
    * cache, then they are processed immediately after starting the scheduler.
    * However, if they have to be downloaded, then these requests are moved
@@ skipping 141 matching lines @@
   var index = this.activeRequests_.indexOf(request);
   if (index < 0)
     console.warn('Request not found.');
   this.activeRequests_.splice(index, 1);
   delete this.requests_[request.getId()];
 
   // Continue handling the most important requests (if started).
   if (this.started_)
     this.continue_();
 };