Remove dead code that was reactivated when fixing overrides.

fpdfsdk/src/formfiller/FFL_FormFiller.cpp

 // 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
 
 #include "../../include/formfiller/FFL_FormFiller.h"
 #include "../../include/formfiller/FFL_Notify.h"
 #include "../../include/formfiller/FFL_CBA_Fontmap.h"
 
@@ skipping 580 matching lines @@
                                           FX_BOOL bRestoreValue) {
   return GetPDFWindow(pPageView, FALSE);
 }
 
 void CFFL_FormFiller::TimerProc() {}
 
 IFX_SystemHandler* CFFL_FormFiller::GetSystemHandler() const {
   return m_pApp->GetSysHandler();
 }
 
-void CFFL_FormFiller::OnKeyStroke(FX_BOOL bKeyDown, FX_DWORD nFlag) {}
-
 void CFFL_FormFiller::EscapeFiller(CPDFSDK_PageView* pPageView,
                                    FX_BOOL bDestroyPDFWindow) {
   m_bValid = FALSE;
 
   FX_RECT rcRect = GetViewBBox(pPageView, m_pWidget);
   InvalidateRect(rcRect.left, rcRect.top, rcRect.right, rcRect.bottom);
 
   if (bDestroyPDFWindow)
     DestroyPDFWindow(pPageView);
 }
@@ skipping 101 matching lines @@
     pWidget->DrawAppearance(pDevice, pUser2Device, CPDF_Annot::Normal, NULL);
 }
 
 void CFFL_Button::OnDrawDeactive(CPDFSDK_PageView* pPageView,
                                  CPDFSDK_Annot* pAnnot,
                                  CFX_RenderDevice* pDevice,
                                  CPDF_Matrix* pUser2Device,
                                  FX_DWORD dwFlags) {
   OnDraw(pPageView, pAnnot, pDevice, pUser2Device, dwFlags);
 }