Cleanup: Use base/files/file_util.h instead of base/file_util.h in apps/ and extensions/

extensions/shell/browser/shell_extension_system.cc

 // 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.
 
 #include "extensions/shell/browser/shell_extension_system.h"
 
 #include <string>
 
-#include "base/file_util.h"
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "extensions/browser/api/app_runtime/app_runtime_api.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/info_map.h"
@@ skipping 172 matching lines @@
   return empty.PassAs<ExtensionSet>();
 }
 
 DeclarativeUserScriptMaster*
 ShellExtensionSystem::GetDeclarativeUserScriptMasterByExtension(
     const ExtensionId& extension_id) {
   return NULL;
 }
 
 }  // namespace extensions