diff --git a/mozilla/layout/base/nsCSSFrameConstructor.cpp b/mozilla/layout/base/nsCSSFrameConstructor.cpp
index bc4c1c52b6f..e73ba3b050d 100644
--- a/mozilla/layout/base/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/base/nsCSSFrameConstructor.cpp
@@ -10449,7 +10449,7 @@ nsCSSFrameConstructor::AttributeChanged(nsIPresContext* aPresContext,
   if (primaryFrame) {
     const nsStyleDisplay* disp;
     primaryFrame->GetStyleData(eStyleStruct_Display,
-                               (nsStyleStruct*&)disp);
+                               (const nsStyleStruct*&)disp);
     if (disp && disp->mAppearance) {
       nsCOMPtr<nsITheme> theme;
       aPresContext->GetTheme(getter_AddRefs(theme));
diff --git a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
index bc4c1c52b6f..e73ba3b050d 100644
--- a/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/html/style/src/nsCSSFrameConstructor.cpp
@@ -10449,7 +10449,7 @@ nsCSSFrameConstructor::AttributeChanged(nsIPresContext* aPresContext,
   if (primaryFrame) {
     const nsStyleDisplay* disp;
     primaryFrame->GetStyleData(eStyleStruct_Display,
-                               (nsStyleStruct*&)disp);
+                               (const nsStyleStruct*&)disp);
     if (disp && disp->mAppearance) {
       nsCOMPtr<nsITheme> theme;
       aPresContext->GetTheme(getter_AddRefs(theme));