diff --git a/mozilla/layout/generic/nsBlockFrame.h b/mozilla/layout/generic/nsBlockFrame.h
index 909cada60f3..2dc4dbcdd70 100644
--- a/mozilla/layout/generic/nsBlockFrame.h
+++ b/mozilla/layout/generic/nsBlockFrame.h
@@ -625,7 +625,7 @@ protected:
     nsIFrame* aOldHead;
     nsBlockFrame* mBlock;
   };
-  friend class nsAutoOOFFrameList;
+  friend struct nsAutoOOFFrameList;
 
   nsFrameList GetOverflowOutOfFlows() const;
   void SetOverflowOutOfFlows(const nsFrameList& aList);