Implement polling part of DriveFileSyncService

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 <string>
 
 #include "base/basictypes.h"
@@ skipping 40 matching lines @@
 // This also maintains conflict information, i.e. a list of conflicting files
 // (at least in the current design).
 // Owned by SyncFileSystemService.
 class RemoteFileSyncService {
  public:
   class Observer {
    public:
     Observer() {}
     virtual ~Observer() {}
 
-    // This is called when there're one or more remote changes available.
+    // This is called when RemoteFileSyncService updates its internal queue
+    // of pending remote changes.
     // |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 OnRemoteChangeAvailable(int64 pending_changes_hint) = 0;
+    virtual void OnRemoteChangeQueueUpdated(int64 pending_changes_hint) = 0;
 
     // This is called when RemoteFileSyncService updates its state.
     virtual void OnRemoteServiceStateUpdated(
         RemoteServiceState state,
         const std::string& description) {}
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Observer);
   };
 
@@ skipping 51 matching lines @@
   // returned by the last OnRemoteServiceStateUpdated notification.
   virtual RemoteServiceState GetCurrentState() const = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RemoteFileSyncService);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_