FWL refcounts never incremented (part 1)

xfa/src/fwl/src/basewidget/include/fwl_listboximp.h

Index: xfa/src/fwl/src/basewidget/include/fwl_listboximp.h
diff --git a/xfa/src/fwl/src/basewidget/include/fwl_listboximp.h b/xfa/src/fwl/src/basewidget/include/fwl_listboximp.h
index 4695a2caec28a5299bfe5536274946db7a961134..d441e5e6a587e0a3f738a1b85383a318ecd4e595 100644
--- a/xfa/src/fwl/src/basewidget/include/fwl_listboximp.h
+++ b/xfa/src/fwl/src/basewidget/include/fwl_listboximp.h
@@ -6,6 +6,9 @@
 
 #ifndef _FWL_LISTBOX_IMP_H
 #define _FWL_LISTBOX_IMP_H
+
+#include "third_party/base/nonstd_unique_ptr.h"
+
 class CFWL_WidgetImp;
 class CFWL_WidgetImpProperties;
 class CFWL_WidgetImpDelegate;
@@ -84,8 +87,8 @@ class CFWL_ListBoxImp : public CFWL_WidgetImp {
   CFX_RectF m_rtClient;
   CFX_RectF m_rtStatic;
   CFX_RectF m_rtConent;
-  IFWL_ScrollBar* m_pHorzScrollBar;
-  IFWL_ScrollBar* m_pVertScrollBar;
+  nonstd::unique_ptr<IFWL_ScrollBar> m_pHorzScrollBar;
+  nonstd::unique_ptr<IFWL_ScrollBar> m_pVertScrollBar;
   FX_DWORD m_dwTTOStyles;
   int32_t m_iTTOAligns;
   FWL_HLISTITEM m_hAnchor;