Get rid of NULLs in xfa/

xfa/fxfa/include/xfa_ffwidget.h

Index: xfa/fxfa/include/xfa_ffwidget.h
diff --git a/xfa/fxfa/include/xfa_ffwidget.h b/xfa/fxfa/include/xfa_ffwidget.h
index 0e58a3406a07a08c4d60d7c31f8f98ed74a798fb..a46a247d286196d683f2f9666af869e8b0d96f3f 100644
--- a/xfa/fxfa/include/xfa_ffwidget.h
+++ b/xfa/fxfa/include/xfa_ffwidget.h
@@ -56,7 +56,7 @@ class CXFA_FFWidget : public CXFA_ContentLayoutItem {
   CXFA_WidgetAcc* GetDataAcc();
   FX_BOOL GetToolTip(CFX_WideString& wsToolTip);
   virtual void RenderWidget(CFX_Graphics* pGS,
-                            CFX_Matrix* pMatrix = NULL,
+                            CFX_Matrix* pMatrix = nullptr,
                             uint32_t dwStatus = 0,
                             int32_t iRotate = 0);
 
@@ -116,8 +116,8 @@ class CXFA_FFWidget : public CXFA_ContentLayoutItem {
   CXFA_FFDoc* GetDoc();
   CXFA_FFApp* GetApp();
   IXFA_AppProvider* GetAppProvider();
-  void InvalidateWidget(const CFX_RectF* pRect = NULL);
-  void AddInvalidateRect(const CFX_RectF* pRect = NULL);
+  void InvalidateWidget(const CFX_RectF* pRect = nullptr);
+  void AddInvalidateRect(const CFX_RectF* pRect = nullptr);
   FX_BOOL GetCaptionText(CFX_WideString& wsCap);
   bool IsFocused();
   void Rotate2Normal(FX_FLOAT& fx, FX_FLOAT& fy);