Replace |CPWL_ComboBox::operator CPWL_Edit()| with explicit method.

fpdfsdk/include/pdfwindow/PWL_ComboBox.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 FPDFSDK_INCLUDE_PDFWINDOW_PWL_COMBOBOX_H_
 #define FPDFSDK_INCLUDE_PDFWINDOW_PWL_COMBOBOX_H_
 
 #include "PWL_Edit.h"
@@ skipping 31 matching lines @@
                           CPDF_Matrix* pUser2Device) override;
   FX_BOOL OnLButtonDown(const CPDF_Point& point, FX_DWORD nFlag) override;
   FX_BOOL OnLButtonUp(const CPDF_Point& point, FX_DWORD nFlag) override;
 };
 
 class CPWL_ComboBox : public CPWL_Wnd {
  public:
   CPWL_ComboBox();
   ~CPWL_ComboBox() override {}
 
-  operator CPWL_Edit*() { return m_pEdit; }
+  CPWL_Edit* GetEdit() const { return m_pEdit; }
 
   // CPWL_Wnd:
   CFX_ByteString GetClassName() const override;
   void OnCreate(PWL_CREATEPARAM& cp) override;
   FX_BOOL OnKeyDown(FX_WORD nChar, FX_DWORD nFlag) override;
   FX_BOOL OnChar(FX_WORD nChar, FX_DWORD nFlag) override;
   void OnNotify(CPWL_Wnd* pWnd,
                 FX_DWORD msg,
                 intptr_t wParam = 0,
                 intptr_t lParam = 0) override;
@@ skipping 35 matching lines @@
   FX_BOOL m_bPopup;
   CPDF_Rect m_rcOldWindow;
   int32_t m_nPopupWhere;
   int32_t m_nSelectItem;
   IPWL_Filler_Notify* m_pFillerNotify;
 
   void* m_pFormFiller;
 };
 
 #endif  // FPDFSDK_INCLUDE_PDFWINDOW_PWL_COMBOBOX_H_