Remove #pragma once. Just from base/ for now.

base/mac/scoped_sending_event.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 BASE_MAC_SCOPED_SENDING_EVENT_H_
 #define BASE_MAC_SCOPED_SENDING_EVENT_H_
-#pragma once
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_nsobject.h"
 #include "base/message_pump_mac.h"
 
 // Nested event loops can pump IPC messages, including
 // script-initiated tab closes, which could release objects that the
 // nested event loop might message.  CrAppProtocol defines how to ask
 // the embedding NSApplication subclass if an event is currently being
@@ skipping 23 matching lines @@
   NSObject<CrAppControlProtocol>* app_;
   BOOL handling_;  // Value of -[app_ handlingSendEvent] at construction.
 
   DISALLOW_COPY_AND_ASSIGN(ScopedSendingEvent);
 };
 
 }  // namespace mac
 }  // namespace base
 
 #endif  // BASE_MAC_SCOPED_SENDING_EVENT_H_