Remove #pragma once from sync

sync/syncable/syncable_enum_conversions.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_SYNCABLE_SYNCABLE_ENUM_CONVERSIONS_H_
 #define SYNC_SYNCABLE_SYNCABLE_ENUM_CONVERSIONS_H_
-#pragma once
 
 // Keep this file in sync with entry_kernel.h.
 
 #include "sync/syncable/entry_kernel.h"
 
 // Utility functions to get the string equivalent for some syncable
 // enums.
 
 namespace syncer {
 namespace syncable {
@@ skipping 20 matching lines @@
 const char* GetStringFieldString(StringField string_field);
 
 const char* GetProtoFieldString(ProtoField proto_field);
 
 const char* GetBitTempString(BitTemp bit_temp);
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // SYNC_SYNCABLE_SYNCABLE_ENUM_CONVERSIONS_H_