Replace homebrew scrollbar in Files app with that of Blink.

ui/file_manager/file_manager/foreground/js/main_scripts.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.
 
 // The include directives are put into Javascript-style comments to prevent
 // parsing errors in non-flattened mode. The flattener still sees them.
 // Note that this makes the flattener to comment out the first line of the
 // included file but that's all right since any javascript file should start
 // with a copyright comment anyway.
 
@@ skipping 150 matching lines @@
 //<include src="ui/files_alert_dialog.js">
 //<include src="ui/files_confirm_dialog.js">
 //<include src="ui/files_menu.js">
 //<include src="ui/gear_menu.js">
 //<include src="ui/list_container.js">
 //<include src="ui/location_line.js">
 //<include src="ui/multi_file_details.js">
 //<include src="ui/multi_profile_share_dialog.js">
 //<include src="ui/progress_center_panel.js">
 //<include src="ui/providers_menu.js">
-//<include src="ui/scrollbar.js">
 //<include src="ui/search_box.js">
 //<include src="ui/share_dialog.js">
 //<include src="ui/single_file_details.js">
 //<include src="ui/suggest_apps_dialog.js">
 //<include src="main_window_component.js">
 //<include src="volume_manager_wrapper.js">
 
 // // For accurate load performance tracking place main.js should be
 // // the last include to include.
 //<include src="main.js">
 
 // Global fileManager reference useful for poking at from the console.
 window.fileManager = fileManager;
 
 // Exports
 window.util = util;
 })();