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

base/memory/raw_scoped_refptr_mismatch_checker.h

 // Copyright (c) 2011 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_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
 #define BASE_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_
-#pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/template_util.h"
 #include "base/tuple.h"
 #include "build/build_config.h"
 
 // It is dangerous to post a task with a T* argument where T is a subtype of
 // RefCounted(Base|ThreadSafeBase), since by the time the parameter is used, the
 // object may already have been deleted since it was not held with a
 // scoped_refptr. Example: http://crbug.com/27191
@@ skipping 103 matching lines @@
                    NeedsScopedRefptrButGetsRawPtr<F>::value ||
                    NeedsScopedRefptrButGetsRawPtr<G>::value ||
                    NeedsScopedRefptrButGetsRawPtr<H>::value) };
 };
 
 }  // namespace internal
 
 }  // namespace base
 
 #endif  // BASE_MEMORY_RAW_SCOPED_REFPTR_MISMATCH_CHECKER_H_