[Sync] Introduce AttachmentStoreForSync class

sync/api/fake_syncable_service.cc

 // 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.
 
 #include "sync/api/fake_syncable_service.h"
 
 #include "base/location.h"
 #include "sync/api/sync_error_factory.h"
 
 namespace syncer {
@@ skipping 52 matching lines @@
 SyncDataList FakeSyncableService::GetAllSyncData(ModelType type) const {
   return SyncDataList();
 }
 
 SyncError FakeSyncableService::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
     const SyncChangeList& change_list) {
   return process_sync_changes_error_;
 }
 
-scoped_ptr<AttachmentStore> FakeSyncableService::GetAttachmentStoreForSync() {
+scoped_ptr<AttachmentStoreForSync>
+FakeSyncableService::GetAttachmentStoreForSync() {
   return attachment_store_ ? attachment_store_->CreateAttachmentStoreForSync()
-                           : scoped_ptr<AttachmentStore>();
+                           : scoped_ptr<AttachmentStoreForSync>();
 }
 
 void FakeSyncableService::SetAttachmentService(
     scoped_ptr<AttachmentService> attachment_service) {
   attachment_service_ = attachment_service.Pass();
 }
 
 }  // namespace syncer