Continue cleaning IFWL classes

xfa/fwl/core/ifwl_timer.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef XFA_FWL_CORE_IFWL_TIMER_H_
 #define XFA_FWL_CORE_IFWL_TIMER_H_
 
 #include "core/fxcrt/fx_system.h"
-#include "xfa/fwl/core/fwl_error.h"
 
 class IFWL_AdapterTimerMgr;
 class IFWL_TimerInfo;
 class IFWL_Widget;
 
 class IFWL_Timer {
  public:
   explicit IFWL_Timer(IFWL_Widget* parent) : m_pWidget(parent) {}
   virtual ~IFWL_Timer() {}
 
   virtual void Run(IFWL_TimerInfo* hTimer) = 0;
   IFWL_TimerInfo* StartTimer(uint32_t dwElapse, bool bImmediately);
 
  protected:
   IFWL_Widget* m_pWidget;  // Not owned.
 };
 
 class IFWL_TimerInfo {
  public:
   explicit IFWL_TimerInfo(IFWL_AdapterTimerMgr* mgr) : m_pMgr(mgr) {
     ASSERT(mgr);
   }
   virtual ~IFWL_TimerInfo() {}
 
-  FWL_Error StopTimer();
+  void StopTimer();
 
- protected:
+ private:
   IFWL_AdapterTimerMgr* m_pMgr;  // Not owned.
 };
 
 #endif  // XFA_FWL_CORE_IFWL_TIMER_H_