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

core/fpdfapi/fpdf_page/cpdf_tilingpattern.h

Index: core/fpdfapi/fpdf_page/cpdf_tilingpattern.h
diff --git a/core/fpdfapi/fpdf_page/cpdf_tilingpattern.h b/core/fpdfapi/fpdf_page/cpdf_tilingpattern.h
index 593630727186b357d2bc6b16e8247066b7f0656c..3e6281036360bf6046350ab3d69c83b02625b0ee 100644
--- a/core/fpdfapi/fpdf_page/cpdf_tilingpattern.h
+++ b/core/fpdfapi/fpdf_page/cpdf_tilingpattern.h
@@ -21,7 +21,7 @@ class CPDF_TilingPattern : public CPDF_Pattern {
  public:
   CPDF_TilingPattern(CPDF_Document* pDoc,
                      CPDF_Object* pPatternObj,
-                     const CFX_Matrix* parentMatrix);
+                     const CFX_Matrix& parentMatrix);
   ~CPDF_TilingPattern() override;
 
   CPDF_TilingPattern* AsTilingPattern() override { return this; }