Remove the GetCaption dataprovider method

xfa/fwl/core/cfwl_combobox.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 "xfa/fwl/core/cfwl_combobox.h"
 
 #include <utility>
 
@@ skipping 138 matching lines @@
 }
 
 void CFWL_ComboBox::EditModifyStylesEx(uint32_t dwStylesExAdded,
                                        uint32_t dwStylesExRemoved) {
   if (GetWidget()) {
     ToComboBox(GetWidget())
         ->EditModifyStylesEx(dwStylesExAdded, dwStylesExRemoved);
   }
 }
 
-void CFWL_ComboBox::GetCaption(IFWL_Widget* pWidget,
-                               CFX_WideString& wsCaption) {}
-
 int32_t CFWL_ComboBox::CountItems(const IFWL_Widget* pWidget) const {
   return m_ItemArray.size();
 }
 
 CFWL_ListItem* CFWL_ComboBox::GetItem(const IFWL_Widget* pWidget,
                                       int32_t nIndex) const {
   if (nIndex < 0 || static_cast<size_t>(nIndex) >= m_ItemArray.size())
     return nullptr;
   return m_ItemArray[nIndex].get();
 }
@@ skipping 73 matching lines @@
 
 void CFWL_ComboBox::SetItemCheckState(IFWL_Widget* pWidget,
                                       CFWL_ListItem* pItem,
                                       uint32_t dwCheckState) {
   static_cast<CFWL_ListItem*>(pItem)->m_dwCheckState = dwCheckState;
 }
 
 FX_FLOAT CFWL_ComboBox::GetListHeight(IFWL_Widget* pWidget) {
   return m_fMaxListHeight;
 }