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

base/metrics/stats_table.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.
 //
 // A StatsTable is a table of statistics.  It can be used across multiple
 // processes and threads, maintaining cheap statistics counters without
 // locking.
 //
 // The goal is to make it very cheap and easy for developers to add
 // counters to code, without having to build one-off utilities or mechanisms
 // to track the counters, and also to allow a single "view" to display
 // the contents of all counters.
 //
 // To achieve this, StatsTable creates a shared memory segment to store
 // the data for the counters.  Upon creation, it has a specific size
 // which governs the maximum number of counters and concurrent
 // threads/processes which can use it.
 //
 
 #ifndef BASE_METRICS_STATS_TABLE_H_
 #define BASE_METRICS_STATS_TABLE_H_
-#pragma once
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_local_storage.h"
 
 namespace base {
@@ skipping 154 matching lines @@
   ThreadLocalStorage::Slot tls_index_;
 
   static StatsTable* global_table_;
 
   DISALLOW_COPY_AND_ASSIGN(StatsTable);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_STATS_TABLE_H_