Get rid of NULLs in xfa/fxbarcode/

xfa/fxbarcode/datamatrix/BC_DataMatrixDecoder.cpp

 // 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
 // Original code is licensed as follows:
 /*
  * Copyright 2007 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ skipping 15 matching lines @@
 
 #include "xfa/fxbarcode/common/BC_CommonBitMatrix.h"
 #include "xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.h"
 #include "xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h"
 #include "xfa/fxbarcode/datamatrix/BC_DataMatrixBitMatrixParser.h"
 #include "xfa/fxbarcode/datamatrix/BC_DataMatrixDataBlock.h"
 #include "xfa/fxbarcode/datamatrix/BC_DataMatrixDecodedBitStreamParser.h"
 #include "xfa/fxbarcode/datamatrix/BC_DataMatrixVersion.h"
 
 CBC_DataMatrixDecoder::CBC_DataMatrixDecoder() {
-  m_rsDecoder = NULL;
+  m_rsDecoder = nullptr;
 }
 void CBC_DataMatrixDecoder::Init() {
   m_rsDecoder =
       new CBC_ReedSolomonDecoder(CBC_ReedSolomonGF256::DataMatrixField);
 }
 CBC_DataMatrixDecoder::~CBC_DataMatrixDecoder() {
   delete m_rsDecoder;
 }
 
 CBC_CommonDecoderResult* CBC_DataMatrixDecoder::Decode(
@@ skipping 53 matching lines @@
   int32_t numECCodewords = codewordBytes.GetSize() - numDataCodewords;
   m_rsDecoder->Decode(&codewordsInts, numECCodewords, e);
   if (e != BCExceptionNO) {
     e = BCExceptionChecksumException;
     return;
   }
   for (i = 0; i < numDataCodewords; i++) {
     codewordBytes[i] = (uint8_t)codewordsInts[i];
   }
 }