Get rid of NULLs in xfa/

xfa/fwl/lightwidget/cfwl_tooltip.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_tooltip.h"
 
 #include <memory>
 
@@ skipping 71 matching lines @@
 }
 
 void CFWL_ToolTip::Hide() {
   static_cast<IFWL_ToolTip*>(m_pIface)->Hide();
 }
 
 CFWL_ToolTip::CFWL_ToolTip() {}
 
 CFWL_ToolTip::~CFWL_ToolTip() {}
 
-CFWL_ToolTip::CFWL_ToolTipDP::CFWL_ToolTipDP() : m_pBitmap(NULL) {
+CFWL_ToolTip::CFWL_ToolTipDP::CFWL_ToolTipDP() : m_pBitmap(nullptr) {
   m_wsCaption = L"";
   m_nInitDelayTime = 500;
   m_nAutoPopDelayTime = 50000;
   m_fAnchor.Set(0.0, 0.0, 0.0, 0.0);
 }
 
 FWL_Error CFWL_ToolTip::CFWL_ToolTipDP::GetCaption(IFWL_Widget* pWidget,
                                                    CFX_WideString& wsCaption) {
   wsCaption = m_wsCaption;
   return FWL_Error::Succeeded;
@@ skipping 13 matching lines @@
 }
 
 CFX_SizeF CFWL_ToolTip::CFWL_ToolTipDP::GetToolTipIconSize(
     IFWL_Widget* pWidget) {
   return m_fIconSize;
 }
 
 CFX_RectF CFWL_ToolTip::CFWL_ToolTipDP::GetAnchor() {
   return m_fAnchor;
 }