Add type cast definitions for CPDF_Array.

core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.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_parser.h"
 const char PDF_CharType[256] = {
     // NUL  SOH  STX  ETX  EOT  ENQ  ACK  BEL  BS   HT   LF   VT   FF   CR   SO
     // SI
@@ skipping 368 matching lines @@
       CFX_ByteString str = pObj->GetString();
       buf << FX_BSTRC("/") << PDF_NameEncode(str);
       break;
     }
     case PDFOBJ_REFERENCE: {
       CPDF_Reference* p = (CPDF_Reference*)pObj;
       buf << " " << p->GetRefObjNum() << FX_BSTRC(" 0 R ");
       break;
     }
     case PDFOBJ_ARRAY: {
-      CPDF_Array* p = (CPDF_Array*)pObj;
+      const CPDF_Array* p = pObj->AsArray();
       buf << FX_BSTRC("[");
       for (FX_DWORD i = 0; i < p->GetCount(); i++) {
         CPDF_Object* pElement = p->GetElement(i);
         if (pElement->GetObjNum()) {
           buf << " " << pElement->GetObjNum() << FX_BSTRC(" 0 R");
         } else {
           buf << pElement;
         }
       }
       buf << FX_BSTRC("]");
@@ skipping 72 matching lines @@
     CPDF_Object* pFound = SearchNumberNode(pKid, num);
     if (pFound) {
       return pFound;
     }
   }
   return NULL;
 }
 CPDF_Object* CPDF_NumberTree::LookupValue(int num) {
   return SearchNumberNode(m_pRoot, num);
 }