Add RemoteFileSyncService interface

chrome/browser/sync_file_system/remote_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_REMOTE_FILE_SYNC_SERVICE_H_
+#define CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_
+
+#include "base/basictypes.h"
+#include "base/observer_list.h"
+#include "chrome/browser/sync_file_system/sync_file_system_callbacks.h"
+
+class GURL;
+
+namespace sync_file_system {
+
+class RemoteChangeObserver;
+class RemoteChangeProcessor;
+
+// This class represents a backing service of the sync filesystem.
+// Owned by SyncFileSystemService.
+class RemoteFileSyncService {
+ public:
+  RemoteFileSyncService();
+  virtual ~RemoteFileSyncService();
+
+  void AddObserver(RemoteChangeObserver* observer);
+  void RemoveObserver(RemoteChangeObserver* observer);

[kinuko, 2012/10/23 08:12:14]

It might be ok to leave them pure virtual too.. then we don't need the protected
methods as well.

[tzik, 2012/10/24 03:32:33]

Done.

+
+  // Registers |origin| to track remote side changes for the |origin|.
+  virtual void RegisterOriginForTrackingChanges(const GURL& origin) = 0;
+
+  // Unregisters |origin| to track remote side changes for the |origin|.
+  virtual void UnregisterOriginForTrackingChanges(const GURL& origin) = 0;
+
+  // Called by the sync engine to process one remote change.
+  // After a change is processed |callback| will be called (to return
+  // the control to the sync engine).
+  virtual void ProcessChange(RemoteChangeProcessor* processor,
+                             StatusCallback& callback) = 0;

[kinuko, 2012/10/23 08:12:14]

I think this should also let the caller know what URL it has worked on (to show
status & to handle suspended sync properly).

In local service case I'm thinking about using this callback type:
typedef base::Callback<void(fileapi::SyncStatusCode status,
fileapi::FileSystemURL& url)> SyncCompletionCallback;

http://codereview.chromium.org/11234025/diff/12/chrome/browser/sync_file_syst...

[tzik, 2012/10/24 03:32:33]

Done.

+
+ protected:
+  void NotifyRemoteChangeAvailable(int64 pending_changes);
+
+ private:
+  ObserverList<RemoteChangeObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(RemoteFileSyncService);
+};
+
+}  // namespace sync_file_system
+
+#endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_