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

fpdfsdk/src/fpdf_sysfontinfo.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 "../include/fsdk_define.h"
 #include "../include/fpdf_sysfontinfo.h"
 
-class CSysFontInfo_Ext : public IFX_SystemFontInfo
+class CSysFontInfo_Ext FX_FINAL : public IFX_SystemFontInfo
 {
 public:
         FPDF_SYSFONTINFO*       m_pInfo;
 
         virtual void            Release()
         {
                 if (m_pInfo->Release)
                         m_pInfo->Release(m_pInfo);
                 delete this;
         }
@@ skipping 133 matching lines @@
         pFontInfoExt->GetFaceName = DefaultGetFaceName;
         pFontInfoExt->GetFont = DefaultGetFont;
         pFontInfoExt->GetFontCharset = DefaultGetFontCharset;
         pFontInfoExt->GetFontData = DefaultGetFontData;
         pFontInfoExt->MapFont = DefaultMapFont;
         pFontInfoExt->Release = DefaultRelease;
         pFontInfoExt->version = 1;
         pFontInfoExt->m_pFontInfo = pFontInfo;
         return pFontInfoExt;
 }