Remove #pragma once from sync

sync/internal_api/public/util/unrecoverable_error_handler.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_UTIL_UNRECOVERABLE_ERROR_HANDLER_H_
 #define SYNC_UTIL_UNRECOVERABLE_ERROR_HANDLER_H_
-#pragma once
 
 #include <string>
 
 #include "base/location.h"
 
 namespace syncer {
 
 class UnrecoverableErrorHandler {
  public:
   // Call this when normal operation detects that the chrome model and the
   // syncer model are inconsistent, or similar.  The ProfileSyncService will
   // try to avoid doing any work to avoid crashing or corrupting things
   // further, and will report an error status if queried.
   virtual void OnUnrecoverableError(const tracked_objects::Location& from_here,
                                     const std::string& message) = 0;
  protected:
   virtual ~UnrecoverableErrorHandler() { }
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_UTIL_UNRECOVERABLE_ERROR_HANDLER_H_