Let SyncBackupManager keep backup data in memory until shutdown. Only persist

sync/internal_api/public/internal_components_factory_impl.h

Index: sync/internal_api/public/internal_components_factory_impl.h
diff --git a/sync/internal_api/public/internal_components_factory_impl.h b/sync/internal_api/public/internal_components_factory_impl.h
index 7c364dce7546cc3319867bf0ff95564dfe275e04..c727509ad1d229febed3312069bbf59cde8cb2ba 100644
--- a/sync/internal_api/public/internal_components_factory_impl.h
+++ b/sync/internal_api/public/internal_components_factory_impl.h
@@ -34,9 +34,9 @@ class SYNC_EXPORT InternalComponentsFactoryImpl
       const std::string& invalidator_client_id) OVERRIDE;
 
   virtual scoped_ptr<syncable::DirectoryBackingStore>
-  BuildDirectoryBackingStore(
-      const std::string& dir_name,
-      const base::FilePath& backing_filepath) OVERRIDE;
+  BuildDirectoryBackingStore(StorageOption storage,
+                             const std::string& dir_name,
+                             const base::FilePath& backing_filepath) OVERRIDE;
 
   virtual Switches GetSwitches() const OVERRIDE;