base::Bind: Cleanup in automation.

chrome/browser/automation/ui_controls_internal.cc

 // Copyright (c) 2010 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.
 
 #include "chrome/browser/automation/ui_controls_internal.h"
 
 namespace ui_controls {
 
-ClickTask::ClickTask(MouseButton button, int state, Task* followup)
+ClickTask::ClickTask(MouseButton button, int state,
+                     const base::Closure& followup)
     : button_(button), state_(state), followup_(followup)  {
 }
 
 ClickTask::~ClickTask() {}
 
 void ClickTask::Run() {
-  if (followup_)
+  if (!followup_.is_null())
     SendMouseEventsNotifyWhenDone(button_, state_, followup_);
   else
     SendMouseEvents(button_, state_);
 }
 
 }  // ui_controls