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

base/test/mock_time_provider.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 helper class used to mock out calls to the static method base::Time::Now.
 //
 // Example usage:
 //
 // typedef base::Time(TimeProvider)();
 // class StopWatch {
@@ skipping 23 matching lines @@
 //       .WillOnce(Return(Time::FromDoubleT(10)));
 //
 //   StopWatch sw(&MockTimeProvider::StaticNow);
 //   sw.Start();  // First call to Now.
 //   TimeDelta elapsed = sw.stop();  // Second call to Now.
 //   ASSERT_EQ(elapsed, TimeDelta::FromSeconds(6));
 // }
 
 #ifndef BASE_TEST_MOCK_TIME_PROVIDER_H_
 #define BASE_TEST_MOCK_TIME_PROVIDER_H_
-#pragma once
 
 #include "base/time.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace base {
 
 class MockTimeProvider {
  public:
   MockTimeProvider();
   ~MockTimeProvider();
 
   MOCK_METHOD0(Now, Time());
 
   static Time StaticNow();
 
  private:
   static MockTimeProvider* instance_;
   DISALLOW_COPY_AND_ASSIGN(MockTimeProvider);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_MOCK_TIME_PROVIDER_H_