Remove #pragma once from sync

sync/internal_api/js_sync_manager_observer.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_JS_SYNC_MANAGER_OBSERVER_H_
 #define SYNC_INTERNAL_API_JS_SYNC_MANAGER_OBSERVER_H_
-#pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "sync/internal_api/public/sync_manager.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 #include "sync/protocol/sync_protocol_error.h"
 
 namespace tracked_objects {
@@ skipping 40 matching lines @@
                     const std::string& name, const JsEventDetails& details);
 
   WeakHandle<JsEventHandler> event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(JsSyncManagerObserver);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_JS_SYNC_MANAGER_OBSERVER_H_