Add type cast definitions for CPDF_Array.

core/src/fpdfapi/fpdf_render/fpdf_render_image.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/fpdfapi/fpdf_module.h"
 #include "../../../include/fpdfapi/fpdf_pageobj.h"
 #include "../../../include/fpdfapi/fpdf_render.h"
 #include "../../../include/fxcodec/fx_codec.h"
@@ skipping 394 matching lines @@
     CPDF_Object* pFilters =
         m_pImageObject->m_pImage->GetStream()->GetDict()->GetElementValue(
             FX_BSTRC("Filter"));
     if (pFilters) {
       if (pFilters->IsName()) {
         CFX_ByteStringC bsDecodeType = pFilters->GetConstString();
         if (bsDecodeType == FX_BSTRC("DCTDecode") ||
             bsDecodeType == FX_BSTRC("JPXDecode")) {
           m_Flags |= FXRENDER_IMAGE_LOSSY;
         }
-      } else if (pFilters->GetType() == PDFOBJ_ARRAY) {
-        CPDF_Array* pArray = (CPDF_Array*)pFilters;
+      } else if (CPDF_Array* pArray = pFilters->AsArray()) {
         for (FX_DWORD i = 0; i < pArray->GetCount(); i++) {
           CFX_ByteStringC bsDecodeType = pArray->GetConstString(i);
           if (bsDecodeType == FX_BSTRC("DCTDecode") ||
               bsDecodeType == FX_BSTRC("JPXDecode")) {
             m_Flags |= FXRENDER_IMAGE_LOSSY;
             break;
           }
         }
       }
     }
@@ skipping 740 matching lines @@
     for (int i = 0; i < size; i++) {
       dest_buf[i] = pTransfer[src_buf[i]];
     }
   } else {
     FXSYS_memcpy(dest_buf, src_buf, dest_pitch * height);
   }
   delete pFunc;
   FX_Free(pTransfer);
   return pMask;
 }