Get rid of NULLs in xfa/

xfa/fwl/basewidget/fwl_datetimepickerimp.h

 // 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
 
 #ifndef XFA_FWL_BASEWIDGET_FWL_DATETIMEPICKERIMP_H_
 #define XFA_FWL_BASEWIDGET_FWL_DATETIMEPICKERIMP_H_
 
 #include <memory>
@@ skipping 157 matching lines @@
   void DisForm_InitDateTimeCalendar();
   void DisForm_InitDateTimeEdit();
   FX_BOOL DisForm_IsMonthCalendarShowed();
   void DisForm_ShowMonthCalendar(FX_BOOL bActivate);
   FWL_WidgetHit DisForm_HitTest(FX_FLOAT fx, FX_FLOAT fy);
   FX_BOOL DisForm_IsNeedShowButton();
   FWL_Error DisForm_Update();
   FWL_Error DisForm_GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize = FALSE);
   FWL_Error DisForm_GetBBox(CFX_RectF& rect);
   FWL_Error DisForm_DrawWidget(CFX_Graphics* pGraphics,
-                               const CFX_Matrix* pMatrix = NULL);
+                               const CFX_Matrix* pMatrix = nullptr);
 
  protected:
   CFX_RectF m_rtBtn;
   CFX_RectF m_rtClient;
   int32_t m_iBtnState;
   int32_t m_iYear;
   int32_t m_iMonth;
   int32_t m_iDay;
   FX_BOOL m_bLBtnDown;
   std::unique_ptr<IFWL_DateTimeEdit> m_pEdit;
@@ skipping 23 matching lines @@
   friend class CFWL_DateTimeEditImpDelegate;
   friend class CFWL_DateTimeCalendar;
   friend class CFWL_DateTimeCalendarImpDelegate;
   friend class CFWL_DateTimePickerImpDelegate;
 };
 class CFWL_DateTimePickerImpDelegate : public CFWL_WidgetImpDelegate {
  public:
   CFWL_DateTimePickerImpDelegate(CFWL_DateTimePickerImp* pOwner);
   void OnProcessMessage(CFWL_Message* pMessage) override;
   void OnDrawWidget(CFX_Graphics* pGraphics,
-                    const CFX_Matrix* pMatrix = NULL) override;
+                    const CFX_Matrix* pMatrix = nullptr) override;
 
  protected:
   void OnFocusChanged(CFWL_Message* pMsg, FX_BOOL bSet = TRUE);
   void OnLButtonDown(CFWL_MsgMouse* pMsg);
   void OnLButtonUp(CFWL_MsgMouse* pMsg);
   void OnMouseMove(CFWL_MsgMouse* pMsg);
   void OnMouseLeave(CFWL_MsgMouse* pMsg);
 
   CFWL_DateTimePickerImp* m_pOwner;
 
  private:
   void DisForm_OnFocusChanged(CFWL_Message* pMsg, FX_BOOL bSet = TRUE);
 };
 
 #endif  // XFA_FWL_BASEWIDGET_FWL_DATETIMEPICKERIMP_H_