Remove NULL in xfa/

xfa/fxfa/include/fxfa_widget.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_FXFA_WIDGET_H_
 #define XFA_FXFA_INCLUDE_FXFA_WIDGET_H_
 
 #include "core/fxcrt/include/fx_coordinates.h"
@@ skipping 52 matching lines @@
   FX_BOOL LoadImageImage();
   FX_BOOL LoadImageEditImage();
   void GetImageDpi(int32_t& iImageXDpi, int32_t& iImageYDpi);
   void GetImageEditDpi(int32_t& iImageXDpi, int32_t& iImageYDpi);
   CXFA_TextLayout* GetCaptionTextLayout();
   CXFA_TextLayout* GetTextLayout();
   CFX_DIBitmap* GetImageImage();
   CFX_DIBitmap* GetImageEditImage();
   void SetImageImage(CFX_DIBitmap* newImage);
   void SetImageEditImage(CFX_DIBitmap* newImage);
-  void UpdateUIDisplay(CXFA_FFWidget* pExcept = NULL);
+  void UpdateUIDisplay(CXFA_FFWidget* pExcept = nullptr);
 
   CXFA_Node* GetDatasets();
   CFGAS_GEFont* GetFDEFont();
   FX_FLOAT GetFontSize();
   FX_ARGB GetTextColor();
   FX_FLOAT GetLineHeight();
   CXFA_WidgetLayoutData* GetWidgetLayoutData();
 
  protected:
   void ProcessScriptTestValidate(CXFA_Validate validate,
@@ skipping 30 matching lines @@
                                   FX_FLOAT& fCalcHeight);
   void InitLayoutData();
   void StartTextLayout(FX_FLOAT& fCalcWidth, FX_FLOAT& fCalcHeight);
 
   CXFA_FFDocView* m_pDocView;
   std::unique_ptr<CXFA_WidgetLayoutData> m_pLayoutData;
   uint32_t m_nRecursionDepth;
 };
 
 #endif  // XFA_FXFA_INCLUDE_FXFA_WIDGET_H_