Use virtual function to retrieve interface pointer

xfa/fwl/lightwidget/cfwl_edit.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_LIGHTWIDGET_CFWL_EDIT_H_
 #define XFA_FWL_LIGHTWIDGET_CFWL_EDIT_H_
 
 #include <vector>
 
+#include "xfa/fwl/basewidget/ifwl_edit.h"
 #include "xfa/fwl/lightwidget/cfwl_widget.h"
 
 class CFWL_WidgetProperties;
 class IFDE_TxtEdtDoRecord;
 
 class CFWL_Edit : public CFWL_Widget {
  public:
   CFWL_Edit();
   ~CFWL_Edit() override;
 
+  IFWL_Edit* GetWidget() override;
+  const IFWL_Edit* GetWidget() const override;
+
   static CFWL_Edit* Create();
   FWL_Error Initialize(const CFWL_WidgetProperties* pProperties = nullptr);
   FWL_Error SetText(const CFX_WideString& wsText);
   int32_t GetTextLength() const;
   FWL_Error GetText(CFX_WideString& wsText,
                     int32_t nStart = 0,
                     int32_t nCount = -1) const;
   FWL_Error ClearText();
   int32_t GetCaretPos() const;
   int32_t SetCaretPos(int32_t nIndex, FX_BOOL bBefore = TRUE);
@@ skipping 27 matching lines @@
   FX_BOOL Paste(const CFX_WideString& wsPaste);
   FX_BOOL Delete();
   void SetScrollOffset(FX_FLOAT fScrollOffset);
   FX_BOOL GetSuggestWords(CFX_PointF pointf,
                           std::vector<CFX_ByteString>& sSuggest);
   FX_BOOL ReplaceSpellCheckWord(CFX_PointF pointf,
                                 const CFX_ByteStringC& bsReplace);
 };
 
 #endif  // XFA_FWL_LIGHTWIDGET_CFWL_EDIT_H_