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

components/sync_driver/generic_change_processor_factory.cc

 // 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.
 
 #include "components/sync_driver/generic_change_processor_factory.h"
 
 #include "components/sync_driver/generic_change_processor.h"
 #include "sync/api/syncable_service.h"
 
 namespace sync_driver {
 
 
 GenericChangeProcessorFactory::GenericChangeProcessorFactory() {}
 
 GenericChangeProcessorFactory::~GenericChangeProcessorFactory() {}
 
 scoped_ptr<GenericChangeProcessor>
 GenericChangeProcessorFactory::CreateGenericChangeProcessor(
     syncer::ModelType type,
     syncer::UserShare* user_share,
     DataTypeErrorHandler* error_handler,
     const base::WeakPtr<syncer::SyncableService>& local_service,
     const base::WeakPtr<syncer::SyncMergeResult>& merge_result,
     SyncApiComponentFactory* sync_factory) {
   DCHECK(user_share);
   return make_scoped_ptr(new GenericChangeProcessor(
-                             type,
-                             error_handler,
-                             local_service,
-                             merge_result,
-                             user_share,
-                             sync_factory,
-                             local_service->GetAttachmentStore())).Pass();
+                             type, error_handler, local_service, merge_result,
+                             user_share, sync_factory,
+                             local_service->GetAttachmentStoreForSync()))
+      .Pass();
 }
 
 }  // namespace sync_driver