Code refactor related to WeakPtrFactory in src/sync module

sync/internal_api/sync_rollback_manager_base.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 SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_BASE_H_
 #define SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_BASE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 115 matching lines @@
 
   bool InitTypeRootNode(ModelType type);
   void InitBookmarkFolder(const std::string& folder);
 
   UserShare share_;
   ObserverList<SyncManager::Observer> observers_;
 
   scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler_;
   ReportUnrecoverableErrorFunction report_unrecoverable_error_function_;
 
-  base::WeakPtrFactory<SyncRollbackManagerBase> weak_ptr_factory_;
-
   scoped_ptr<SyncEncryptionHandler> dummy_handler_;
 
   bool initialized_;
 
+  base::WeakPtrFactory<SyncRollbackManagerBase> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncRollbackManagerBase);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_BASE_H_