Implement SyncFileSystemService::GetFileSyncStatus method

chrome/browser/sync_file_system/local_file_sync_service.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_SYNC_FILE_SYSTEM_LOCAL_FILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_FILE_SYNC_SERVICE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 34 matching lines @@
     // This is called when there're one or more local changes available.
     // |pending_changes_hint| indicates the pending queue length to help sync
     // scheduling but the value may not be accurately reflect the real-time
     // value.
     virtual void OnLocalChangeAvailable(int64 pending_changes_hint) = 0;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Observer);
   };
 
+  typedef base::Callback<void(bool has_pending_changes)>
+      HasPendingLocalChangeCallback;
+
   LocalFileSyncService();
   virtual ~LocalFileSyncService();
 
   void Shutdown();
 
   void MaybeInitializeFileSystemContext(
       const GURL& app_origin,
       const std::string& service_name,
       fileapi::FileSystemContext* file_system_context,
       const fileapi::SyncStatusCallback& callback);
 
   void AddChangeObserver(Observer* observer);
 
   // Registers |url| to wait until sync is enabled for |url|.
   // |on_syncable_callback| is to be called when |url| becomes syncable
   // (i.e. when we have no pending writes and the file is successfully locked
   // for sync).
   // Calling this method again while this already has another URL waiting
   // for sync will overwrite the previously registered URL.
   void RegisterURLForWaitingSync(const fileapi::FileSystemURL& url,
                                  const base::Closure& on_syncable_callback);
 
   // Synchronize one (or a set of) local change(s) to the remote server
   // using |processor|.
   // |processor| must have same or longer lifetime than this service.
   void ProcessLocalChange(LocalChangeProcessor* processor,
                           const fileapi::SyncFileCallback& callback);
 
+  // Returns true via |callback| if the given file |url| has local pending
+  // changes.
+  void HasPendingLocalChanges(
+      const fileapi::FileSystemURL& url,
+      const HasPendingLocalChangeCallback& callback);
+
   // Returns the metadata of a remote file pointed by |url|.
   virtual void GetLocalFileMetadata(
       const fileapi::FileSystemURL& url,
       const fileapi::SyncFileMetadataCallback& callback);
 
   // RemoteChangeProcessor overrides.
   virtual void PrepareForProcessRemoteChange(
       const fileapi::FileSystemURL& url,
       const PrepareChangeCallback& callback) OVERRIDE;
   virtual void ApplyRemoteChange(
@@ skipping 66 matching lines @@
   fileapi::SyncFileCallback local_sync_callback_;
 
   ObserverList<Observer> change_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalFileSyncService);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_FILE_SYNC_SERVICE_H_