Get rid of NULLs in xfa/

xfa/fxfa/include/xfa_ffpageview.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_FXFA_INCLUDE_XFA_FFPAGEVIEW_H_
 #define XFA_FXFA_INCLUDE_XFA_FFPAGEVIEW_H_
 
 #include "xfa/fxfa/parser/xfa_doclayout.h"
@@ skipping 43 matching lines @@
 
   CXFA_FFPageView* m_pPageView;
   CXFA_FFWidget* m_hCurWidget;
   uint32_t m_dwFilter;
   FX_BOOL m_bIgnorerelevant;
   CXFA_LayoutItemIterator m_sIterator;
 };
 typedef CFX_ArrayTemplate<CXFA_FFWidget*> CXFA_WidgetArray;
 class CXFA_TabParam {
  public:
-  CXFA_TabParam() : m_pWidget(NULL) {}
+  CXFA_TabParam() : m_pWidget(nullptr) {}
   ~CXFA_TabParam() {}
 
   CXFA_FFWidget* m_pWidget;
   CXFA_WidgetArray m_Children;
 };
 class CXFA_FFTabOrderPageWidgetIterator : public IXFA_WidgetIterator {
  public:
   CXFA_FFTabOrderPageWidgetIterator(CXFA_FFPageView* pPageView,
                                     uint32_t dwFilter);
   ~CXFA_FFTabOrderPageWidgetIterator() override;
@@ skipping 21 matching lines @@
                       FX_BOOL bMarsterPage = FALSE);
 
   CXFA_WidgetArray m_TabOrderWidgetArray;
   CXFA_FFPageView* m_pPageView;
   uint32_t m_dwFilter;
   int32_t m_iCurWidget;
   FX_BOOL m_bIgnorerelevant;
 };
 
 #endif  // XFA_FXFA_INCLUDE_XFA_FFPAGEVIEW_H_