diff --git a/core/fpdfdoc/cpdf_annot.cpp b/core/fpdfdoc/cpdf_annot.cpp
index e9829b0..39707b8 100644
--- a/core/fpdfdoc/cpdf_annot.cpp
+++ b/core/fpdfdoc/cpdf_annot.cpp
@@ -247,9 +247,9 @@
 }
 
 // static
-CFX_FloatRect CPDF_Annot::RectFromQuadPoints(CPDF_Dictionary* pAnnotDict,
+CFX_FloatRect CPDF_Annot::RectFromQuadPoints(const CPDF_Dictionary* pAnnotDict,
                                              size_t nIndex) {
-  CPDF_Array* pArray = pAnnotDict->GetArrayFor("QuadPoints");
+  const CPDF_Array* pArray = pAnnotDict->GetArrayFor("QuadPoints");
   if (!pArray)
     return CFX_FloatRect();
   return RectFromQuadPointsArray(pArray, nIndex);
diff --git a/core/fpdfdoc/cpdf_annot.h b/core/fpdfdoc/cpdf_annot.h
index d24e497..00de807 100644
--- a/core/fpdfdoc/cpdf_annot.h
+++ b/core/fpdfdoc/cpdf_annot.h
@@ -71,7 +71,7 @@
                                                size_t nIndex);
   static CFX_FloatRect BoundingRectFromQuadPoints(
       const CPDF_Dictionary* pAnnotDict);
-  static CFX_FloatRect RectFromQuadPoints(CPDF_Dictionary* pAnnotDict,
+  static CFX_FloatRect RectFromQuadPoints(const CPDF_Dictionary* pAnnotDict,
                                           size_t nIndex);
   static size_t QuadPointCount(const CPDF_Array* pArray);