Make down-conversion explicit from CFX_ByteString to CFX_ByteStringC.

xfa/fxbarcode/oned/BC_OnedCodaBarReader.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 88 matching lines @@
   CFX_ByteString temp = result;
   for (int32_t k = 1; k < result.GetLength(); k++) {
     if (ArrayContains(STARTEND_ENCODING, result[k])) {
       if ((k + 1) != result.GetLength()) {
         result.Delete(1, k);
         k = 1;
       }
     }
   }
   if (result.GetLength() < 5) {
-    int32_t index = temp.Find(result.Mid(1, result.GetLength() - 1));
+    int32_t index =
+        temp.Find(result.Mid(1, result.GetLength() - 1).AsByteStringC());
     if (index == len - (result.GetLength() - 1)) {
       e = BCExceptionNotFound;
       return "";
     }
   }
   if (result.GetLength() > minCharacterLength) {
     result = result.Mid(1, result.GetLength() - 2);
   } else {
     e = BCExceptionNotFound;
     return "";
@@ skipping 83 matching lines @@
   }
   if ((wideCounters == 2) || (wideCounters == 3)) {
     for (int32_t k = 0; k < 22; k++) {
       if (CHARACTER_ENCODINGS[k] == pattern) {
         return (ALPHABET_STRING)[k];
       }
     }
   }
   return '!';
 }