Add type cast definitions for CPDF_Array.

core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp

Index: core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
index cdf2104f82f01868492dbda1346ba73873942b86..2754223f3ecc95a709da5b4c76482d4683ae6580 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_image.cpp
@@ -412,8 +412,7 @@ FX_BOOL CPDF_ImageRenderer::StartRenderDIBSource() {
             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") ||