Remove NULL in xfa/

xfa/fxfa/parser/xfa_basic_imp.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_PARSER_XFA_BASIC_IMP_H_
 #define XFA_FXFA_PARSER_XFA_BASIC_IMP_H_
 
 #include "xfa/fgas/crt/fgas_stream.h"
@@ skipping 19 matching lines @@
   IFX_Stream* Retain() override;
   uint32_t GetAccessModes() const override;
   int32_t GetLength() const override;
   int32_t Seek(FX_STREAMSEEK eSeek, int32_t iOffset) override;
   int32_t GetPosition() override;
   FX_BOOL IsEOF() const override;
   int32_t ReadData(uint8_t* pBuffer, int32_t iBufferSize) override;
   int32_t ReadString(FX_WCHAR* pStr,
                      int32_t iMaxLength,
                      FX_BOOL& bEOS,
-                     int32_t const* pByteSize = NULL) override;
+                     int32_t const* pByteSize = nullptr) override;
   int32_t WriteData(const uint8_t* pBuffer, int32_t iBufferSize) override;
   int32_t WriteString(const FX_WCHAR* pStr, int32_t iLength) override;
   void Flush() override {}
   FX_BOOL SetLength(int32_t iLength) override;
   int32_t GetBOM(uint8_t bom[4]) const override;
   uint16_t GetCodePage() const override;
   uint16_t SetCodePage(uint16_t wCodePage) override;
   IFX_Stream* CreateSharedStream(uint32_t dwAccess,
                                  int32_t iOffset,
                                  int32_t iLength) override;
 
   virtual void Lock();
   virtual void Unlock();
 
   CFX_WideString GetSrcText() const;
 
  protected:
   CFX_WideString m_wsBuffer;
   int32_t m_iPosition;
   int32_t m_iRefCount;
 };
 
 #endif  // XFA_FXFA_PARSER_XFA_BASIC_IMP_H_