Remove unneeded uses of logging.h in header files.

base/timer.h

 // Copyright (c) 2006-2008 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.
 
 // OneShotTimer and RepeatingTimer provide a simple timer API.  As the names
 // suggest, OneShotTimer calls you back once after a time delay expires.
 // RepeatingTimer on the other hand calls you back periodically with the
 // prescribed time interval.
 //
 // OneShotTimer and RepeatingTimer both cancel the timer when they go out of
@@ skipping 28 matching lines @@
 // the same arguments.
 
 #ifndef BASE_TIMER_H_
 #define BASE_TIMER_H_
 
 // IMPORTANT: If you change timer code, make sure that all tests (including
 // disabled ones) from timer_unittests.cc pass locally. Some are disabled
 // because they're flaky on the buildbot, but when you run them locally you
 // should be able to tell the difference.
 
+#include "base/logging.h"
 #include "base/task.h"
 #include "base/time.h"
 
 class MessageLoop;
 
 namespace base {
 
 //-----------------------------------------------------------------------------
 // This class is an implementation detail of OneShotTimer and RepeatingTimer.
 // Please do not use this class directly.
@@ skipping 202 matching lines @@
   const ReceiverMethod method_;
   const TimeDelta delay_;
 
   OneShotTimer<DelayTimer<Receiver> > timer_;
   Time trigger_time_;
 };
 
 }  // namespace base
 
 #endif  // BASE_TIMER_H_