Add type cast definitions for CPDF_Array.

core/src/fpdfapi/fpdf_page/fpdf_page_doc.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_page.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fdrm/fx_crypt.h"
 #include "../fpdf_font/font_int.h"
@@ skipping 325 matching lines @@
       case PDFCS_DEVICEGRAY:
         pDefaultCS = pColorSpaces->GetElementValue(FX_BSTRC("DefaultGray"));
         break;
       case PDFCS_DEVICECMYK:
         pDefaultCS = pColorSpaces->GetElementValue(FX_BSTRC("DefaultCMYK"));
         break;
     }
     return pDefaultCS ? GetColorSpace(pDefaultCS, nullptr) : pCS;
   }
 
-  if (pCSObj->GetType() != PDFOBJ_ARRAY)
-    return nullptr;
-  CPDF_Array* pArray = (CPDF_Array*)pCSObj;
-  if (pArray->GetCount() == 0)
+  CPDF_Array* pArray = pCSObj->AsArray();
+  if (!pArray || pArray->GetCount() == 0)
     return nullptr;
   if (pArray->GetCount() == 1)
     return GetColorSpace(pArray->GetElementValue(0), pResources);
 
   CPDF_CountedColorSpace* csData = nullptr;
   auto it = m_ColorSpaceMap.find(pCSObj);
   if (it != m_ColorSpaceMap.end()) {
     csData = it->second;
     if (csData->get()) {
       return csData->AddRef();
@@ skipping 238 matching lines @@
 }
 
 CPDF_CountedPattern* CPDF_DocPageData::FindPatternPtr(
     CPDF_Object* pPatternObj) const {
   if (!pPatternObj)
     return nullptr;
 
   auto it = m_PatternMap.find(pPatternObj);
   return it != m_PatternMap.end() ? it->second : nullptr;
 }