Make code compile with clang_use_chrome_plugin (part VI)

xfa/fwl/lightwidget/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/lightwidget/cfwl_combobox.h"
 
 #include <utility>
 
@@ skipping 272 matching lines @@
 
 CFWL_ComboBox::~CFWL_ComboBox() {}
 
 CFWL_ComboBox::CFWL_ComboBoxDP::CFWL_ComboBoxDP() {
   m_fItemHeight = 0;
   m_fMaxListHeight = 0;
 }
 
 CFWL_ComboBox::CFWL_ComboBoxDP::~CFWL_ComboBoxDP() {}
 
+FWL_Error CFWL_ComboBox::CFWL_ComboBoxDP::GetCaption(
+    IFWL_Widget* pWidget,
+    CFX_WideString& wsCaption) {
+  return FWL_Error::Succeeded;
+}
+
 int32_t CFWL_ComboBox::CFWL_ComboBoxDP::CountItems(IFWL_Widget* pWidget) {
   return m_ItemArray.size();
 }
 
 IFWL_ListItem* CFWL_ComboBox::CFWL_ComboBoxDP::GetItem(IFWL_Widget* pWidget,
                                                        int32_t nIndex) {
   if (nIndex < 0 || static_cast<size_t>(nIndex) >= m_ItemArray.size())
     return nullptr;
 
   return m_ItemArray[nIndex].get();
@@ skipping 117 matching lines @@
     IFWL_Widget* pWidget,
     IFWL_ListItem* pItem,
     uint32_t dwCheckState) {
   static_cast<CFWL_ComboBoxItem*>(pItem)->m_dwCheckState = dwCheckState;
   return FWL_Error::Succeeded;
 }
 
 FX_FLOAT CFWL_ComboBox::CFWL_ComboBoxDP::GetListHeight(IFWL_Widget* pWidget) {
   return m_fMaxListHeight;
 }
+
+CFWL_ComboBoxItem::CFWL_ComboBoxItem() : m_pDIB(nullptr), m_pData(nullptr) {}
+
+CFWL_ComboBoxItem::~CFWL_ComboBoxItem() {}