XFA: merge patch from CL 729293003, use FX_ArraySize for safety

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 579 matching lines @@
 
     FX_STRSIZE          m_Length;
 private:
 
     void*                       operator new (size_t) throw()
     {
         return NULL;
     }
 };
 typedef const CFX_WideStringC&  FX_WSTR;
-#define FX_WSTRC(wstr) CFX_WideStringC(wstr, sizeof(wstr) / sizeof(FX_WCHAR) - 1)
+#define FX_WSTRC(wstr) CFX_WideStringC(wstr, FX_ArraySize(wstr) - 1)
 struct CFX_StringDataW {
 
     long                m_nRefs;
 
     FX_STRSIZE  m_nDataLength;
 
     FX_STRSIZE  m_nAllocLength;
 
     FX_WCHAR    m_String[1];
 };
@@ skipping 233 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