Assert CPDF_Pattern always has a valid CPDF_Document pointer.

Same for CPDF_DocPageData.

Change-Id: I8f2f559123dbb2f3623d957e4074d5f9d191797f
Reviewed-on: https://pdfium-review.googlesource.com/4501
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

1 files changed, 7 insertions, 11 deletions

diff --git a/core/fpdfapi/page/cpdf_shadingpattern.cpp b/core/fpdfapi/page/cpdf_shadingpattern.cpp
index 133d32ff3a..dae5ec356c 100644
--- a/core/fpdfapi/page/cpdf_shadingpattern.cpp
+++ b/core/fpdfapi/page/cpdf_shadingpattern.cpp
@@ -31,27 +31,23 @@ CPDF_ShadingPattern::CPDF_ShadingPattern(CPDF_Document* pDoc,
                                          CPDF_Object* pPatternObj,
                                          bool bShading,
                                          const CFX_Matrix& parentMatrix)
-    : CPDF_Pattern(SHADING,
-                   pDoc,
-                   bShading ? nullptr : pPatternObj,
-                   parentMatrix),
+    : CPDF_Pattern(pDoc, bShading ? nullptr : pPatternObj, parentMatrix),
       m_ShadingType(kInvalidShading),
       m_bShadingObj(bShading),
       m_pShadingObj(pPatternObj),
       m_pCS(nullptr),
       m_pCountedCS(nullptr) {
+  assert(document());
   if (!bShading) {
-    CPDF_Dictionary* pDict = m_pPatternObj->GetDict();
-    m_Pattern2Form = pDict->GetMatrixFor("Matrix");
-    m_pShadingObj = pDict->GetDirectObjectFor("Shading");
-    m_Pattern2Form.Concat(parentMatrix);
+    m_pShadingObj = pattern_obj()->GetDict()->GetDirectObjectFor("Shading");
+    SetPatternToFormMatrix();
   }
 }
 
 CPDF_ShadingPattern::~CPDF_ShadingPattern() {
   CPDF_ColorSpace* pCS = m_pCountedCS ? m_pCountedCS->get() : nullptr;
-  if (pCS && m_pDocument) {
-    auto* pPageData = m_pDocument->GetPageData();
+  if (pCS) {
+    auto* pPageData = document()->GetPageData();
     if (pPageData)
       pPageData->ReleaseColorSpace(pCS->GetArray());
   }
@@ -89,7 +85,7 @@ bool CPDF_ShadingPattern::Load() {
   if (!pCSObj)
     return false;
 
-  CPDF_DocPageData* pDocPageData = m_pDocument->GetPageData();
+  CPDF_DocPageData* pDocPageData = document()->GetPageData();
   m_pCS = pDocPageData->GetColorSpace(pCSObj, nullptr);
   if (m_pCS)
     m_pCountedCS = pDocPageData->FindColorSpacePtr(m_pCS->GetArray());