CPDF_Document::LoadPattern() and friends always have a valid matrix.

core/fpdfapi/fpdf_parser/cpdf_document.cpp

Index: core/fpdfapi/fpdf_parser/cpdf_document.cpp
diff --git a/core/fpdfapi/fpdf_parser/cpdf_document.cpp b/core/fpdfapi/fpdf_parser/cpdf_document.cpp
index c92e177dcca6c1451b3310597ea49c60b3c448c2..ead1ac0455f73aa5d95ae6f0cc43783f421e2011 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_document.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_document.cpp
@@ -753,7 +753,7 @@ CPDF_ColorSpace* CPDF_Document::LoadColorSpace(CPDF_Object* pCSObj,
 
 CPDF_Pattern* CPDF_Document::LoadPattern(CPDF_Object* pPatternObj,
                                          FX_BOOL bShading,
-                                         const CFX_Matrix* matrix) {
+                                         const CFX_Matrix& matrix) {
   return m_pDocPage->GetPattern(pPatternObj, bShading, matrix);
 }