Remove #pragma once from sync

sync/notifier/registration_manager.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.
 //
 // A class that manages the registration of types for server-issued
 // notifications.
 
 #ifndef SYNC_NOTIFIER_REGISTRATION_MANAGER_H_
 #define SYNC_NOTIFIER_REGISTRATION_MANAGER_H_
-#pragma once
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time.h"
 #include "base/timer.h"
 // For invalidation::InvalidationListener::RegistrationState.
 #include "google/cacheinvalidation/include/invalidation-listener.h"
 #include "google/cacheinvalidation/include/types.h"
@@ skipping 156 matching lines @@
   RegistrationStatusMap registration_statuses_;
   // Weak pointer.
   invalidation::InvalidationClient* invalidation_client_;
 
   DISALLOW_COPY_AND_ASSIGN(RegistrationManager);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_REGISTRATION_MANAGER_H_