Cleanup FWL Event and Message code.

xfa/fwl/core/cfwl_scrollbar.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_scrollbar.h"
 
 #include <algorithm>
 #include <memory>
@@ skipping 357 matching lines @@
   }
   if (m_iMouseWheel) {
     FWL_SCBCODE dwCode = m_iMouseWheel < 0 ? FWL_SCBCODE::StepForward
                                            : FWL_SCBCODE::StepBackward;
     DoScroll(dwCode, m_fTrackPos);
   }
   return true;
 }
 
 bool CFWL_ScrollBar::OnScroll(FWL_SCBCODE dwCode, FX_FLOAT fPos) {
-  bool bRet = true;
   CFWL_EvtScroll ev;
   ev.m_iScrollCode = dwCode;
   ev.m_pSrcTarget = this;
   ev.m_fPos = fPos;
-  ev.m_pRet = &bRet;
   DispatchEvent(&ev);
-  return bRet;
+  return true;
 }
 
 void CFWL_ScrollBar::OnProcessMessage(CFWL_Message* pMessage) {
   if (!pMessage)
     return;
 
   CFWL_MessageType dwMsgCode = pMessage->GetClassID();
   if (dwMsgCode == CFWL_MessageType::Mouse) {
     CFWL_MsgMouse* pMsg = static_cast<CFWL_MsgMouse*>(pMessage);
     switch (pMsg->m_dwCmd) {
@@ skipping 158 matching lines @@
 
 void CFWL_ScrollBar::Timer::Run(CFWL_TimerInfo* pTimerInfo) {
   CFWL_ScrollBar* pButton = static_cast<CFWL_ScrollBar*>(m_pWidget);
 
   if (pButton->m_pTimerInfo)
     pButton->m_pTimerInfo->StopTimer();
 
   if (!pButton->SendEvent())
     pButton->m_pTimerInfo = StartTimer(0, true);
 }