Make down-conversion explicit from CFX_Widetring to CFX_WideStringC.

xfa/fxbarcode/oned/BC_OnedCode39Writer.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 342 matching lines @@
   }
   return encodedContents;
 }
 void CBC_OnedCode39Writer::RenderResult(const CFX_WideStringC& contents,
                                         uint8_t* code,
                                         int32_t codeLength,
                                         FX_BOOL isDevice,
                                         int32_t& e) {
   CFX_WideString encodedCon = encodedContents(contents, e);
   BC_EXCEPTION_CHECK_ReturnVoid(e);
-  CBC_OneDimWriter::RenderResult(encodedCon, code, codeLength, isDevice, e);
+  CBC_OneDimWriter::RenderResult(encodedCon.AsWideStringC(), code, codeLength,
+                                 isDevice, e);
 }