Revert "Make m_pShadingObj a CPDF_Stream instead of CPDF_Object."

There appear to be a bunch of corpus tests which fail with this change such
as FAILURE: shading1.pdf

This reverts commit 85361b227ad6786d2aeef8409b79a8d077a26ee9.

Make m_pShadingObj a CPDF_Stream instead of CPDF_Object.

This object is required to be a stream and was being converted as such. With
the new type checking this caused us to pass a nullptr where previously we'd
have, incorrectly, cast a CPDF_Dictionary to a CPDF_Stream.

This CL changes the m_pShadingObj to always be a CPDF_Stream. Then, we never
go down the bad code path because we check if m_pShadingObj is nullptr earlier
and bail out.

BUG=chromium:547706
TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1414283003 .

2 files changed, 6 insertions, 5 deletions

diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index bd4319df11..b12a65a844 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -1128,9 +1128,10 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
     bbox = m_BBox;
   }
   if (pShading->m_ShadingType >= 4) {
-    bbox.Intersect(_GetShadingBBox(
-        pShading->m_pShadingObj, pShading->m_ShadingType, &pObj->m_Matrix,
-        pShading->m_pFunctions, pShading->m_nFuncs, pShading->m_pCS));
+    bbox.Intersect(_GetShadingBBox(ToStream(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;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
index d06f481138..7b04d8cd33 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
@@ -71,12 +71,12 @@ CPDF_ShadingPattern::CPDF_ShadingPattern(CPDF_Document* pDoc,
     CPDF_Dictionary* pDict = m_pPatternObj->GetDict();
     ASSERT(pDict != NULL);
     m_Pattern2Form = pDict->GetMatrix(FX_BSTRC("Matrix"));
-    m_pShadingObj = ToStream(pDict->GetElementValue(FX_BSTRC("Shading")));
+    m_pShadingObj = pDict->GetElementValue(FX_BSTRC("Shading"));
     if (parentMatrix) {
       m_Pattern2Form.Concat(*parentMatrix);
     }
   } else {
-    m_pShadingObj = ToStream(pPatternObj);
+    m_pShadingObj = pPatternObj;
   }
   m_ShadingType = 0;
   m_pCS = NULL;