[SyncFS] Create SyncWorkerTest

chrome/browser/sync_file_system/drive_backend/sync_engine.h

Index: chrome/browser/sync_file_system/drive_backend/sync_engine.h
diff --git a/chrome/browser/sync_file_system/drive_backend/sync_engine.h b/chrome/browser/sync_file_system/drive_backend/sync_engine.h
index 5d33e0df0c26e88823b8e8fd8195408fff258f2d..516fa79245dfd006403cb8867d968df3c64f2c49 100644
--- a/chrome/browser/sync_file_system/drive_backend/sync_engine.h
+++ b/chrome/browser/sync_file_system/drive_backend/sync_engine.h
@@ -144,11 +144,6 @@ class SyncEngine : public RemoteFileSyncService,
              ExtensionServiceInterface* extension_service,
              SigninManagerBase* signin_manager);
 
-  // TODO(peria): Migrate this method into test code.
-  // This method is not thread safe, because it requires to access metadata
-  // database which may live in another thread.
-  void UpdateRegisteredAppsForTesting();
-
   SyncStatusCallback TrackCallback(const SyncStatusCallback& callback);
 
   scoped_ptr<drive::DriveServiceInterface> drive_service_;