Use smart pointers for class owned pointers

fpdfsdk/pdfwindow/PWL_Wnd.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 <map>
 
 #include "fpdfsdk/pdfwindow/PWL_ScrollBar.h"
 #include "fpdfsdk/pdfwindow/PWL_Utils.h"
@@ skipping 62 matching lines @@
 void CPWL_Timer::TimerProc(int32_t idEvent) {
   auto it = GetPWLTimeMap().find(idEvent);
   if (it == GetPWLTimeMap().end())
     return;
 
   CPWL_Timer* pTimer = it->second;
   if (pTimer->m_pAttached)
     pTimer->m_pAttached->TimerProc();
 }
 
-CPWL_TimerHandler::CPWL_TimerHandler() : m_pTimer(nullptr) {}
+CPWL_TimerHandler::CPWL_TimerHandler() {}
 
-CPWL_TimerHandler::~CPWL_TimerHandler() {
-  delete m_pTimer;
-}
+CPWL_TimerHandler::~CPWL_TimerHandler() {}
 
 void CPWL_TimerHandler::BeginTimer(int32_t nElapse) {
   if (!m_pTimer)
-    m_pTimer = new CPWL_Timer(this, GetSystemHandler());
+    m_pTimer.reset(new CPWL_Timer(this, GetSystemHandler()));
 
   if (m_pTimer)
     m_pTimer->SetPWLTimer(nElapse);
 }
 
 void CPWL_TimerHandler::EndTimer() {
   if (m_pTimer)
     m_pTimer->KillPWLTimer();
 }
 
@@ skipping 937 matching lines @@
   return FALSE;
 }
 
 FX_BOOL CPWL_Wnd::IsALTpressed(uint32_t nFlag) const {
   if (CFX_SystemHandler* pSystemHandler = GetSystemHandler()) {
     return pSystemHandler->IsALTKeyDown(nFlag);
   }
 
   return FALSE;
 }