Cleanup caret show/hide code

xfa/fwl/core/cfwl_comboedit.cpp

 // Copyright 2016 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_comboedit.h"
 
 #include <memory>
 #include <utility>
@@ skipping 21 matching lines @@
   AddSelRange(0);
 }
 
 void CFWL_ComboEdit::FlagFocus(bool bSet) {
   if (bSet) {
     m_pProperties->m_dwStates |= FWL_WGTSTATE_Focused;
     return;
   }
 
   m_pProperties->m_dwStates &= ~FWL_WGTSTATE_Focused;
-  ShowCaret(false);
+  HideCaret(nullptr);
 }
 
 void CFWL_ComboEdit::OnProcessMessage(CFWL_Message* pMessage) {
   if (!pMessage)
     return;
 
   bool backDefault = true;
   switch (pMessage->GetType()) {
     case CFWL_Message::Type::SetFocus: {
       m_pProperties->m_dwStates |= FWL_WGTSTATE_Focused;
@@ skipping 13 matching lines @@
         m_pOuter->SetFocus(true);
       }
       break;
     }
     default:
       break;
   }
   if (backDefault)
     CFWL_Edit::OnProcessMessage(pMessage);
 }