diff --git a/mozilla/layout/base/public/nsIStyleContext.h b/mozilla/layout/base/public/nsIStyleContext.h
index 33a2f2b879e..b9c14b15e43 100644
--- a/mozilla/layout/base/public/nsIStyleContext.h
+++ b/mozilla/layout/base/public/nsIStyleContext.h
@@ -195,6 +195,8 @@ public:
   // call this to prevent context from getting shared
   virtual void  ForceUnique(void) = 0;
 
+  NS_IMETHOD RemapStyle(nsIPresContext* aPresContext) = 0;
+
   // call if you change style data after creation
   virtual void    RecalcAutomaticData(nsIPresContext* aPresContext) = 0;