Remove dead code that was reactivated when fixing overrides.

fpdfsdk/include/formfiller/FFL_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_FORMFILLER_FFL_COMBOBOX_H_
 #define FPDFSDK_INCLUDE_FORMFILLER_FFL_COMBOBOX_H_
 
 #include "../../../core/include/fxcrt/fx_string.h"
@@ skipping 29 matching lines @@
   void SetActionData(CPDFSDK_PageView* pPageView,
                      CPDF_AAction::AActionType type,
                      const PDFSDK_FieldAction& fa) override;
   FX_BOOL IsActionDataChanged(CPDF_AAction::AActionType type,
                               const PDFSDK_FieldAction& faOld,
                               const PDFSDK_FieldAction& faNew) override;
   void SaveState(CPDFSDK_PageView* pPageView) override;
   void RestoreState(CPDFSDK_PageView* pPageView) override;
   CPWL_Wnd* ResetPDFWindow(CPDFSDK_PageView* pPageView,
                            FX_BOOL bRestoreValue) override;
-  void OnKeyStroke(FX_BOOL bKeyDown, FX_DWORD nFlag) override;
 
   // IPWL_FocusHandler:
   void OnSetFocus(CPWL_Wnd* pWnd) override;
   void OnKillFocus(CPWL_Wnd* pWnd) override;
 
   // IPWL_Edit_Notify:
   void OnAddUndo(CPWL_Edit* pEdit) override;
 
  private:
   CFX_WideString GetSelectExportText();
 
   CBA_FontMap* m_pFontMap;
   FFL_ComboBoxState m_State;
 };
 
 #endif  // FPDFSDK_INCLUDE_FORMFILLER_FFL_COMBOBOX_H_