Change IFWL_Widget to store a single delegate.

xfa/fxfa/app/xfa_ffchoicelist.h

Index: xfa/fxfa/app/xfa_ffchoicelist.h
diff --git a/xfa/fxfa/app/xfa_ffchoicelist.h b/xfa/fxfa/app/xfa_ffchoicelist.h
index 712959d56ccc3d3835e9659fc606ea1057c2d14c..84c5fac5990cd1ff631460d64720f6482c67f8b7 100644
--- a/xfa/fxfa/app/xfa_ffchoicelist.h
+++ b/xfa/fxfa/app/xfa_ffchoicelist.h
@@ -18,10 +18,6 @@ class CXFA_FFListBox : public CXFA_FFField {
   // CXFA_FFField
   FX_BOOL LoadWidget() override;
   FX_BOOL OnKillFocus(CXFA_FFWidget* pNewWidget) override;
-  void OnProcessMessage(CFWL_Message* pMessage) override;
-  void OnProcessEvent(CFWL_Event* pEvent) override;
-  void OnDrawWidget(CFX_Graphics* pGraphics,
-                    const CFX_Matrix* pMatrix = nullptr) override;
 
   void OnSelectChanged(IFWL_Widget* pWidget, const CFX_Int32Array& arrSels);
   void SetItemState(int32_t nIndex, FX_BOOL bSelected);
@@ -34,8 +30,6 @@ class CXFA_FFListBox : public CXFA_FFField {
   FX_BOOL IsDataChanged() override;
 
   uint32_t GetAlignment();
-
-  IFWL_WidgetDelegate* m_pOldDelegate;
 };
 
 class CXFA_FFComboBox : public CXFA_FFField {
@@ -67,12 +61,6 @@ class CXFA_FFComboBox : public CXFA_FFField {
   FX_BOOL Delete() override;
   FX_BOOL DeSelect() override;
 
-  // IFWL_WidgetDelegate
-  void OnProcessMessage(CFWL_Message* pMessage) override;
-  void OnProcessEvent(CFWL_Event* pEvent) override;
-  void OnDrawWidget(CFX_Graphics* pGraphics,
-                    const CFX_Matrix* pMatrix = nullptr) override;
-
   virtual void OpenDropDownList();
 
   void OnTextChanged(IFWL_Widget* pWidget, const CFX_WideString& wsChanged);
@@ -96,7 +84,6 @@ class CXFA_FFComboBox : public CXFA_FFField {
   void FWLEventSelChange(CXFA_EventParam* pParam);
 
   CFX_WideString m_wsNewValue;
-  IFWL_WidgetDelegate* m_pOldDelegate;
 };
 
 #endif  // XFA_FXFA_APP_XFA_FFCHOICELIST_H_