Make CFX_WideString::FromUTF8() take a CFX_ByteStringC argument.

xfa/fxfa/parser/xfa_utils_imp.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 "xfa/fxfa/parser/xfa_utils.h"
 
 #include "core/fxcrt/include/fx_ext.h"
 #include "xfa/fde/xml/fde_xml_imp.h"
@@ skipping 374 matching lines @@
   }
   FX_DOUBLE dValue = (dwFractional / 4294967296.0);
   dValue = nIntegral + (nIntegral >= 0 ? dValue : -dValue);
   if (nExponent != 0) {
     dValue *= FXSYS_pow(10, (FX_FLOAT)nExponent);
   }
   return dValue;
 }
 
 FX_DOUBLE XFA_ByteStringToDouble(const CFX_ByteStringC& szStringVal) {
-  CFX_WideString wsValue =
-      CFX_WideString::FromUTF8(szStringVal.c_str(), szStringVal.GetLength());
+  CFX_WideString wsValue = CFX_WideString::FromUTF8(szStringVal);
   return XFA_WideStringToDouble(wsValue);
 }
 
 int32_t XFA_MapRotation(int32_t nRotation) {
   nRotation = nRotation % 360;
   nRotation = nRotation < 0 ? nRotation + 360 : nRotation;
   return nRotation;
 }