Reduce header dependencies in base/

base/idle_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.
 
 // IdleTimer is a recurring Timer which runs only when the system is idle.
 // System Idle time is defined as not having any user keyboard or mouse
 // activity for some period of time.  Because the timer is user dependant, it
 // is possible for the timer to never fire.
 //
 // Usage should be for low-priority work, and may look like this:
@@ skipping 15 matching lines @@
 // Such a thread should be running a MessageLoopForUI.
 
 #ifndef BASE_IDLE_TIMER_H_
 #define BASE_IDLE_TIMER_H_
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "base/basictypes.h"
-#include "base/task.h"
 #include "base/timer.h"
 
 namespace base {
 
 // Function prototype - Get the number of milliseconds that the user has been
 // idle.
 typedef bool (*IdleTimeSource)(int32 *milliseconds_interval_since_last_event);
 
 class IdleTimer {
  public:
@@ skipping 41 matching lines @@
   OneShotTimer<IdleTimer> timer_;
 
   IdleTimeSource idle_time_source_;
 
   DISALLOW_COPY_AND_ASSIGN(IdleTimer);
 };
 
 }  // namespace base
 
 #endif  // BASE_IDLE_TIMER_H_