Get rid of FX_LPCSTR cast.

core/include/fxcrt/fx_string.h

 // 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
 
 #ifndef _FX_STRING_H_
 #define _FX_STRING_H_
 class CFX_ByteStringC;
 class CFX_ByteString;
@@ skipping 166 matching lines @@
     CFX_ByteString(FX_BSTR bstrc);
 
     CFX_ByteString(FX_BSTR bstrc1, FX_BSTR bstrc2);
 
     ~CFX_ByteString();
 
     static CFX_ByteString       FromUnicode(FX_LPCWSTR ptr, FX_STRSIZE len = -1);
 
     static CFX_ByteString       FromUnicode(const CFX_WideString& str);
 
+    // Explicit conversion to raw string
+    FX_LPCSTR c_str() const
+    {
+        return m_pData ? m_pData->m_String : "";
+    }
+
+    // Implicit conversion to C-style string -- deprecated
     operator                            FX_LPCSTR() const
     {
         return m_pData ? m_pData->m_String : "";
     }
 
     operator                            FX_LPCBYTE() const
     {
         return m_pData ? (FX_LPCBYTE)m_pData->m_String : NULL;
     }
 
@@ skipping 647 matching lines @@
 CFX_ByteString  FX_UTF8Encode(FX_LPCWSTR pwsStr, FX_STRSIZE len);
 inline CFX_ByteString   FX_UTF8Encode(FX_WSTR wsStr)
 {
     return FX_UTF8Encode(wsStr.GetPtr(), wsStr.GetLength());
 }
 inline CFX_ByteString   FX_UTF8Encode(const CFX_WideString &wsStr)
 {
     return FX_UTF8Encode(wsStr.c_str(), wsStr.GetLength());
 }
 #endif