gdata: Implement periodic file system update checks.

chrome/browser/chromeos/extensions/file_browser_event_router.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_BROWSER_EVENT_ROUTER_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_BROWSER_EVENT_ROUTER_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 138 matching lines @@
       const chromeos::disks::DiskMountManager::MountPointInfo& mount_info);
 
   void RemoveBrowserFromVector(const std::string& path);
 
   // Used to create a window of a standard size, and add it to a list
   // of tracked browser windows in case that device goes away.
   void OpenFileBrowse(const std::string& url,
                       const std::string& device_path,
                       bool small);
 
+  // Returns the GDataFileSystem for the current profile.
+  gdata::GDataFileSystem* GetFileSystem() const;
+
   scoped_refptr<FileWatcherDelegate> delegate_;
   WatcherMap file_watchers_;
   scoped_ptr<FileBrowserNotifications> notifications_;
   Profile* profile_;
   base::Lock lock_;
 
   bool current_gdata_operation_failed_;
   int last_active_gdata_operation_count_;
 
   DISALLOW_COPY_AND_ASSIGN(FileBrowserEventRouter);
@@ skipping 20 matching lines @@
 
   FileBrowserEventRouterFactory();
   virtual ~FileBrowserEventRouterFactory();
 
   // ProfileKeyedServiceFactory:
   virtual scoped_refptr<RefcountedProfileKeyedService> BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
 };
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_BROWSER_EVENT_ROUTER_H_