Remove implicit cast from CFX_ByteString to (const char*).

xfa/fxbarcode/oned/BC_OnedUPCAWriter.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 52 matching lines @@
     }
   }
   return filtercontents;
 }
 int32_t CBC_OnedUPCAWriter::CalcChecksum(const CFX_ByteString& contents) {
   int32_t odd = 0;
   int32_t even = 0;
   int32_t j = 1;
   for (int32_t i = contents.GetLength() - 1; i >= 0; i--) {
     if (j % 2) {
-      odd += FXSYS_atoi(contents.Mid(i, 1));
+      odd += FXSYS_atoi(contents.Mid(i, 1).c_str());
     } else {
-      even += FXSYS_atoi(contents.Mid(i, 1));
+      even += FXSYS_atoi(contents.Mid(i, 1).c_str());
     }
     j++;
   }
   int32_t checksum = (odd * 3 + even) % 10;
   checksum = (10 - checksum) % 10;
   return (checksum);
 }
 uint8_t* CBC_OnedUPCAWriter::Encode(const CFX_ByteString& contents,
                                     BCFORMAT format,
                                     int32_t& outWidth,
@@ skipping 191 matching lines @@
   }
   FX_Free(pCharPos);
 }
 void CBC_OnedUPCAWriter::RenderResult(const CFX_WideStringC& contents,
                                       uint8_t* code,
                                       int32_t codeLength,
                                       FX_BOOL isDevice,
                                       int32_t& e) {
   CBC_OneDimWriter::RenderResult(contents, code, codeLength, isDevice, e);
 }