Fix Wvarargs warning in XFA error code.

xfa/fxfa/fm2js/xfa_lexer.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/fm2js/xfa_lexer.h"
 
 #include "core/fxcrt/include/fx_ext.h"
 
@@ skipping 514 matching lines @@
     if (uHash == keyword.m_uHash)
       return keyword.m_type;
     if (uHash < keyword.m_uHash)
       iEnd = iMid - 1;
     else
       iStart = iMid + 1;
   } while (iStart <= iEnd);
   return TOKidentifier;
 }
 
-void CXFA_FMLexer::Error(XFA_FM_ERRMSG msg, ...) {
+void CXFA_FMLexer::Error(const FX_WCHAR* msg, ...) {
   m_pErrorInfo->linenum = m_uCurrentLine;
-  const FX_WCHAR* lpMessageInfo = XFA_FM_ErrorMsg(msg);
   va_list ap;
   va_start(ap, msg);
-  m_pErrorInfo->message.FormatV(lpMessageInfo, ap);
+  m_pErrorInfo->message.FormatV(msg, ap);
   va_end(ap);
 }
 
 FX_BOOL CXFA_FMLexer::HasError() const {
   if (m_pErrorInfo->message.IsEmpty()) {
     return FALSE;
   }
   return TRUE;
 }