Use smart pointers for class owned pointers in xfa/fwl/theme

xfa/fwl/theme/cfwl_scrollbartp.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_THEME_CFWL_SCROLLBARTP_H_
 #define XFA_FWL_THEME_CFWL_SCROLLBARTP_H_
 
+#include <memory>
+
 #include "xfa/fwl/theme/cfwl_widgettp.h"
 
 class CFWL_ScrollBarTP : public CFWL_WidgetTP {
  public:
   CFWL_ScrollBarTP();
   ~CFWL_ScrollBarTP() override;
 
   // CFWL_WidgetTP
   bool IsValidWidget(IFWL_Widget* pWidget) override;
   uint32_t SetThemeID(IFWL_Widget* pWidget,
@@ skipping 30 matching lines @@
                      FWLTHEME_DIRECTION eDict,
                      FWLTHEME_STATE eState,
                      CFX_Matrix* pMatrix = nullptr);
   void DrawPaw(CFX_Graphics* pGraphics,
                const CFX_RectF* pRect,
                FX_BOOL bVert,
                FWLTHEME_STATE eState,
                CFX_Matrix* pMatrix = nullptr);
   void SetThemeData(uint32_t dwID);
 
-  struct SBThemeData* m_pThemeData;
+  std::unique_ptr<SBThemeData> m_pThemeData;
 };
 
 #endif  // XFA_FWL_THEME_CFWL_SCROLLBARTP_H_