Get rid of NULLs in core/

core/fxcrt/include/fx_xml.h

Index: core/fxcrt/include/fx_xml.h
diff --git a/core/fxcrt/include/fx_xml.h b/core/fxcrt/include/fx_xml.h
index 8816e2eae188f980e5eafb367bb7ce28ca996e05..0e8c82b10373f2e37fadaf9b48415347a5259697 100644
--- a/core/fxcrt/include/fx_xml.h
+++ b/core/fxcrt/include/fx_xml.h
@@ -53,13 +53,13 @@ class CXML_Element {
   static CXML_Element* Parse(const void* pBuffer,
                              size_t size,
                              FX_BOOL bSaveSpaceChars = FALSE,
-                             FX_FILESIZE* pParsedSize = NULL);
+                             FX_FILESIZE* pParsedSize = nullptr);
   static CXML_Element* Parse(IFX_FileRead* pFile,
                              FX_BOOL bSaveSpaceChars = FALSE,
-                             FX_FILESIZE* pParsedSize = NULL);
+                             FX_FILESIZE* pParsedSize = nullptr);
   static CXML_Element* Parse(IFX_BufferRead* pBuffer,
                              FX_BOOL bSaveSpaceChars = FALSE,
-                             FX_FILESIZE* pParsedSize = NULL);
+                             FX_FILESIZE* pParsedSize = nullptr);
 
   CXML_Element(const CFX_ByteStringC& qSpace, const CFX_ByteStringC& tagName);
   CXML_Element(const CFX_ByteStringC& qTagName);