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

base/threading/sequenced_worker_pool_task_runner.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_THREADING_SEQUENCED_WORKER_POOL_TASK_RUNNER_H_
 #define BASE_THREADING_SEQUENCED_WORKER_POOL_TASK_RUNNER_H_
-#pragma once
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/time.h"
 
 namespace tracked_objects {
@@ skipping 36 matching lines @@
   const scoped_refptr<SequencedWorkerPool> pool_;
 
   const SequencedWorkerPool::SequenceToken token_;
 
   DISALLOW_COPY_AND_ASSIGN(SequencedWorkerPoolTaskRunner);
 };
 
 }  // namespace base
 
 #endif  // BASE_THREADING_SEQUENCED_WORKER_POOL_TASK_RUNNER_H_