Move xfa/fwl/core to xfa/fwl.

xfa/fwl/core/cfwl_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_CFWL_TIMER_H_
-#define XFA_FWL_CORE_CFWL_TIMER_H_
-
-#include "core/fxcrt/fx_system.h"
-
-class CFWL_TimerInfo;
-class CFWL_Widget;
-
-class CFWL_Timer {
- public:
-  explicit CFWL_Timer(CFWL_Widget* parent) : m_pWidget(parent) {}
-  virtual ~CFWL_Timer() {}
-
-  virtual void Run(CFWL_TimerInfo* hTimer) = 0;
-  CFWL_TimerInfo* StartTimer(uint32_t dwElapse, bool bImmediately);
-
- protected:
-  CFWL_Widget* m_pWidget;  // Not owned.
-};
-
-#endif  // XFA_FWL_CORE_CFWL_TIMER_H_