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

fpdfsdk/src/fpdfview.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/fpdfview.h"
 #include "../include/fsdk_rendercontext.h"
 #include "../include/fpdf_progressive.h"
@@ skipping 271 matching lines @@
         catch (...) {
                 delete pParser;
                 SetLastError(FPDF_ERR_UNKNOWN);
                 return NULL;
         }
         return pParser->GetDocument();
 }
 
 extern void CheckUnSupportError(CPDF_Document * pDoc, FX_DWORD err_code);
 
-class CMemFile: public IFX_FileRead, public CFX_Object
+class CMemFile FX_FINAL: public IFX_FileRead, public CFX_Object
 {
 public:
         CMemFile(FX_BYTE* pBuf, FX_FILESIZE size):m_pBuf(pBuf),m_size(size) {}
 
         virtual void                    Release() {delete this;}
         virtual FX_FILESIZE             GetSize() {return m_size;}
         virtual FX_BOOL                 ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) 
         {
                 if(offset+size > (FX_DWORD)m_size) return FALSE;
                 FXSYS_memcpy(buffer, m_pBuf+offset, size);
@@ skipping 567 matching lines @@
 {
         if (document == NULL)
                 return NULL;
         if (name == NULL || name[0] == 0) 
                 return NULL;
 
         CPDF_Document* pDoc = (CPDF_Document*)document;
         CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
         return name_tree.LookupNamedDest(pDoc, name);
 }