Get rid of NULLs in xfa/fxbarcode/

xfa/fxbarcode/oned/BC_OnedUPCAReader.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 2008 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ skipping 11 matching lines @@
 
 #include "core/fxcrt/include/fx_basic.h"
 #include "xfa/fxbarcode/BC_Reader.h"
 #include "xfa/fxbarcode/oned/BC_OneDReader.h"
 #include "xfa/fxbarcode/oned/BC_OneDimReader.h"
 #include "xfa/fxbarcode/oned/BC_OnedEAN13Reader.h"
 #include "xfa/fxbarcode/oned/BC_OnedUPCAReader.h"
 #include "xfa/fxbarcode/utils.h"
 
 CBC_OnedUPCAReader::CBC_OnedUPCAReader() {
-  m_ean13Reader = NULL;
+  m_ean13Reader = nullptr;
 }
 void CBC_OnedUPCAReader::Init() {
   m_ean13Reader = new CBC_OnedEAN13Reader;
 }
 CBC_OnedUPCAReader::~CBC_OnedUPCAReader() {
   delete m_ean13Reader;
 }
 CFX_ByteString CBC_OnedUPCAReader::DecodeRow(int32_t rowNumber,
                                              CBC_CommonBitArray* row,
                                              int32_t hints,
@@ skipping 43 matching lines @@
 }
 CFX_ByteString CBC_OnedUPCAReader::MaybeReturnResult(CFX_ByteString& result,
                                                      int32_t& e) {
   if (result[0] == '0') {
     result.Delete(0);
     return result;
   }
   e = BCExceptionFormatException;
   return "";
 }