Compile file_manager and eliminate gyp v1 from Files App!

ui/file_manager/externs/gallery_foreground.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.
 
 /**
  * BackgroundComponents.
  * @constructor
  * @struct
  */
 function BackgroundComponents() {
   /**
    * @type {!Object<string>}
    */
   this.stringData;
 
   /**
    * @type {!VolumeManager}
    */
   this.volumeManager;
 }
 
 /**
- * File Manager. This definition is required by
- * ui/file_manager/file_manager/foreground/js/ui/file_manager_dialog_base.js.
- *
- * @constructor
- * @struct
- */
-function FileManager() {}
-
-/**
  * A global flag which indicates whether it is in tests or not. This is set in
  * gallery/js/background.js.
  *
  * @type {boolean}
  */
 Window.prototype.IN_TEST;
 
 /**
  * @type {string}
  */
 Entry.prototype.cachedUrl;