Remove unused sysbtn code

xfa/fwl/cfwl_sysbtn.h

Index: xfa/fwl/cfwl_sysbtn.h
diff --git a/xfa/fwl/cfwl_sysbtn.h b/xfa/fwl/cfwl_sysbtn.h
deleted file mode 100644
index e79b438f6a726f00880eac12ab5c4868588144c8..0000000000000000000000000000000000000000
--- a/xfa/fwl/cfwl_sysbtn.h
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright 2016 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_CFWL_SYSBTN_H_
-#define XFA_FWL_CFWL_SYSBTN_H_
-
-#include "core/fxcrt/fx_coordinates.h"
-
-#define FWL_SYSBUTTONSTATE_Hover 0x0001
-#define FWL_SYSBUTTONSTATE_Pressed 0x0002
-#define FWL_SYSBUTTONSTATE_Disabled 0x0010
-
-class CFWL_SysBtn {
- public:
-  CFWL_SysBtn();
-  ~CFWL_SysBtn();
-
-  bool IsDisabled() const;
-  uint32_t GetPartState() const;
-
-  void SetNormal();
-  void SetPressed();
-  void SetHover();
-  void SetDisabled(bool bDisabled);
-
-  CFX_RectF m_rtBtn;
-  uint32_t m_dwState;
-};
-
-#endif  // XFA_FWL_CFWL_SYSBTN_H_