Make CFX_WideString(const CFX_WideString&) explicit.

core/fxcrt/fx_basic_wstring.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
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cctype>
@@ skipping 768 matching lines @@
                                             uint16_t codepage) {
   return CFX_CharMap::GetWideString(codepage, str);
 }
 
 // static
 CFX_WideString CFX_WideString::FromUTF8(const CFX_ByteStringC& str) {
   if (str.IsEmpty())
     return CFX_WideString();
 
   CFX_UTF8Decoder decoder;
-  for (FX_STRSIZE i = 0; i < str.GetLength(); i++) {
+  for (FX_STRSIZE i = 0; i < str.GetLength(); i++)
     decoder.Input(str[i]);
-  }
-  return decoder.GetResult();
+
+  return CFX_WideString(decoder.GetResult());
 }
 
 // static
 CFX_WideString CFX_WideString::FromUTF16LE(const unsigned short* wstr,
                                            FX_STRSIZE wlen) {
   if (!wstr || 0 == wlen) {
     return CFX_WideString();
   }
 
   CFX_WideString result;
@@ skipping 184 matching lines @@
       FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, nullptr, 0);
   CFX_WideString wstr;
   if (dest_len) {
     FX_WCHAR* dest_buf = wstr.GetBuffer(dest_len);
     FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, dest_buf,
                               dest_len);
     wstr.ReleaseBuffer(dest_len);
   }
   return wstr;
 }