Revert of [Sync] Refactor AttachmentStore classes. Introduce concept of referrer.

components/sync_driver/sync_api_component_factory.h

 // Copyright 2014 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 COMPONENTS_SYNC_DRIVER_SYNC_API_COMPONENT_FACTORY_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_API_COMPONENT_FACTORY_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "sync/api/syncable_service.h"
@@ skipping 19 matching lines @@
   //
   // |store_birthday| is the store birthday.  Must not be empty.
   //
   // |model_type| is the model type this AttachmentService will be used with.
   //
   // |delegate| is optional delegate for AttachmentService to notify about
   // asynchronous events (AttachmentUploaded). Pass NULL if delegate is not
   // provided. AttachmentService doesn't take ownership of delegate, the pointer
   // must be valid throughout AttachmentService lifetime.
   virtual scoped_ptr<syncer::AttachmentService> CreateAttachmentService(
-      scoped_ptr<syncer::AttachmentStore> attachment_store,
+      const scoped_refptr<syncer::AttachmentStore>& attachment_store,
       const syncer::UserShare& user_share,
       const std::string& store_birthday,
       syncer::ModelType model_type,
       syncer::AttachmentService::Delegate* delegate) = 0;
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_API_COMPONENT_FACTORY_H_