Fix CFWL_WidgetImpDelegate hierarchy.

xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp

Index: xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp
diff --git a/xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp b/xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp
index ec44d9c2de481a0e4f274138482ac30a113bc574..a9d75d0fad970b2556594cafc8513742792c30d1 100644
--- a/xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp
+++ b/xfa/src/fwl/src/basewidget/fwl_scrollbarimp.cpp
@@ -137,14 +137,12 @@ FX_DWORD CFWL_ScrollBarImp::GetClassID() const {
 FWL_ERR CFWL_ScrollBarImp::Initialize() {
   _FWL_ERR_CHECK_RETURN_VALUE_IF_FAIL(CFWL_WidgetImp::Initialize(),
                                       FWL_ERR_Indefinite);
-  m_pDelegate = (IFWL_WidgetDelegate*)new CFWL_ScrollBarImpDelegate(this);
+  m_pDelegate = new CFWL_ScrollBarImpDelegate(this);
   return FWL_ERR_Succeeded;
 }
 FWL_ERR CFWL_ScrollBarImp::Finalize() {
-  if (m_pDelegate) {
-    delete (CFWL_ScrollBarImpDelegate*)m_pDelegate;
-    m_pDelegate = NULL;
-  }
+  delete m_pDelegate;
+  m_pDelegate = nullptr;
   return CFWL_WidgetImp::Finalize();
 }
 FWL_ERR CFWL_ScrollBarImp::GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize) {