Make CFX_WideString(const CFX_WideString&) explicit.

xfa/fxbarcode/cbc_code128.cpp

 // Copyright 2016 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
 /*
  * Copyright 2011 ZXing authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ skipping 35 matching lines @@
 FX_BOOL CBC_Code128::Encode(const CFX_WideStringC& contents,
                             FX_BOOL isDevice,
                             int32_t& e) {
   if (contents.IsEmpty()) {
     e = BCExceptionNoContents;
     return FALSE;
   }
   BCFORMAT format = BCFORMAT_CODE_128;
   int32_t outWidth = 0;
   int32_t outHeight = 0;
-  CFX_WideString content = contents;
+  CFX_WideString content(contents);
   if (contents.GetLength() % 2 &&
       ((CBC_OnedCode128Writer*)m_pBCWriter)->GetType() == BC_CODE128_C) {
     content += '0';
   }
   CFX_WideString encodeContents = ((CBC_OnedCode128Writer*)m_pBCWriter)
                                       ->FilterContents(content.AsStringC());
   m_renderContents = encodeContents;
   CFX_ByteString byteString = encodeContents.UTF8Encode();
   uint8_t* data = static_cast<CBC_OnedCode128Writer*>(m_pBCWriter)
                       ->Encode(byteString, format, outWidth, outHeight, e);
@@ skipping 27 matching lines @@
                                    int32_t& e) {
   CFX_WideString str;
   return str;
 }
 
 CFX_WideString CBC_Code128::Decode(CFX_DIBitmap* pBitmap, int32_t& e) {
   CBC_BufferedImageLuminanceSource source(pBitmap);
   CBC_GlobalHistogramBinarizer binarizer(&source);
   CBC_BinaryBitmap bitmap(&binarizer);
   CFX_ByteString str = m_pBCReader->Decode(&bitmap, 0, e);
-  BC_EXCEPTION_CHECK_ReturnValue(e, FX_WSTRC(L""));
+  BC_EXCEPTION_CHECK_ReturnValue(e, CFX_WideString());
   return CFX_WideString::FromUTF8(str.AsStringC());
 }