Get rid of NULLs in xfa/fxbarcode/

xfa/fxbarcode/common/BC_WhiteRectangleDetector.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 2010 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ skipping 179 matching lines @@
   int32_t dist = DistanceL2(aX, aY, bX, bY);
   float xStep = (bX - aX) / dist;
   float yStep = (bY - aY) / dist;
   for (int32_t i = 0; i < dist; i++) {
     int32_t x = Round(aX + i * xStep);
     int32_t y = Round(aY + i * yStep);
     if (m_image->Get(x, y)) {
       return new CBC_ResultPoint((FX_FLOAT)x, (FX_FLOAT)y);
     }
   }
-  return NULL;
+  return nullptr;
 }
 int32_t CBC_WhiteRectangleDetector::DistanceL2(FX_FLOAT aX,
                                                FX_FLOAT aY,
                                                FX_FLOAT bX,
                                                FX_FLOAT bY) {
   float xDiff = aX - bX;
   float yDiff = aY - bY;
   return Round((float)sqrt(xDiff * xDiff + yDiff * yDiff));
 }
 
@@ skipping 42 matching lines @@
     }
   } else {
     for (int32_t y = a; y <= b; y++) {
       if (m_image->Get(fixed, y)) {
         return TRUE;
       }
     }
   }
   return FALSE;
 }