Make m_pShadingObj a CPDF_Stream instead of CPDF_Object.

core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp

Index: core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 3295b7f9e034875582758e7efa8cffddfc95c80d..777bd3fce2b93d063d0a7720e5e56c4f8a2f99bd 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -1151,10 +1151,9 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
     bbox = m_BBox;
   }
   if (pShading->m_ShadingType >= 4) {
-    bbox.Intersect(_GetShadingBBox(ToStream(pShading->m_pShadingObj),
-                                   pShading->m_ShadingType, &pObj->m_Matrix,
-                                   pShading->m_pFunctions, pShading->m_nFuncs,
-                                   pShading->m_pCS));
+    bbox.Intersect(_GetShadingBBox(
+        pShading->m_pShadingObj, pShading->m_ShadingType, &pObj->m_Matrix,
+        pShading->m_pFunctions, pShading->m_nFuncs, pShading->m_pCS));
   }
   pObj->m_Left = bbox.left;
   pObj->m_Right = bbox.right;