Make CFX_WideString(const CFX_WideString&) explicit.

xfa/fxbarcode/cbc_datamatrix.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 25 matching lines @@
 CBC_DataMatrix::~CBC_DataMatrix() {
   delete (m_pBCReader);
   delete (m_pBCWriter);
 }
 
 FX_BOOL CBC_DataMatrix::Encode(const CFX_WideStringC& contents,
                                FX_BOOL isDevice,
                                int32_t& e) {
   int32_t outWidth = 0;
   int32_t outHeight = 0;
-  uint8_t* data = ((CBC_DataMatrixWriter*)m_pBCWriter)
-                      ->Encode(contents, outWidth, outHeight, e);
+  uint8_t* data =
+      ((CBC_DataMatrixWriter*)m_pBCWriter)
+          ->Encode(CFX_WideString(contents), outWidth, outHeight, e);
   BC_EXCEPTION_CHECK_ReturnValue(e, FALSE);
   ((CBC_TwoDimWriter*)m_pBCWriter)->RenderResult(data, outWidth, outHeight, e);
   FX_Free(data);
   BC_EXCEPTION_CHECK_ReturnValue(e, FALSE);
   return TRUE;
 }
 
 FX_BOOL CBC_DataMatrix::RenderDevice(CFX_RenderDevice* device,
                                      const CFX_Matrix* matrix,
                                      int32_t& e) {
@@ skipping 13 matching lines @@
                                       int32_t& e) {
   CFX_WideString str;
   return str;
 }
 
 CFX_WideString CBC_DataMatrix::Decode(CFX_DIBitmap* pBitmap, int32_t& e) {
   CBC_BufferedImageLuminanceSource source(pBitmap);
   CBC_GlobalHistogramBinarizer binarizer(&source);
   CBC_BinaryBitmap bitmap(&binarizer);
   CFX_ByteString retStr = 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(retStr.AsStringC());
 }