Remove #pragma once from sync

sync/internal_api/public/engine/passive_model_worker.h

 // 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.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_ENGINE_PASSIVE_MODEL_WORKER_H_
 #define SYNC_INTERNAL_API_PUBLIC_ENGINE_PASSIVE_MODEL_WORKER_H_
-#pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "sync/internal_api/public/engine/model_safe_worker.h"
 #include "sync/internal_api/public/util/syncer_error.h"
 
 class MessageLoop;
 
 namespace syncer {
 
@@ skipping 13 matching lines @@
   virtual ~PassiveModelWorker();
 
   const MessageLoop* const sync_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(PassiveModelWorker);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ENGINE_PASSIVE_MODEL_WORKER_H_