pdfium: Fix all -Wdelete-non-virtual-dtor violations on Mac.

core/src/fxcrt/fx_arabic.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_ARABIC_IMP
 #define _FX_ARABIC_IMP
-class CFX_BidiChar : public IFX_BidiChar, public CFX_Object
+class CFX_BidiChar FX_FINAL : public IFX_BidiChar, public CFX_Object
 {
 public:
     CFX_BidiChar();
     virtual void                Release()
     {
         delete this;
     }
     virtual void                SetPolicy(FX_BOOL bSeparateNeutral = TRUE)
     {
         m_bSeparateNeutral = bSeparateNeutral;
     }
     virtual FX_BOOL             AppendChar(FX_WCHAR wch);
     virtual FX_BOOL             EndChar();
     virtual FX_INT32    GetBidiInfo(FX_INT32 &iStart, FX_INT32 &iCount);
     virtual void                Reset();
 protected:
     FX_BOOL             m_bSeparateNeutral;
     FX_INT32    m_iCurStart;
     FX_INT32    m_iCurCount;
     FX_INT32    m_iCurBidi;
     FX_INT32    m_iLastBidi;
     FX_INT32    m_iLastStart;
     FX_INT32    m_iLastCount;
 };
 #endif