diff --git a/components/gfx_traits/lib.rs b/components/gfx_traits/lib.rs
index 72c1b373e2b..89ddeb512bf 100644
--- a/components/gfx_traits/lib.rs
+++ b/components/gfx_traits/lib.rs
@@ -211,11 +211,6 @@ impl ScrollRootId {
     pub fn fragment_type(&self) -> FragmentType {
         FragmentType::from_usize(self.0 & 3)
     }
-
-    #[inline]
-    pub fn to_stacking_context_id(&self) -> StackingContextId {
-        StackingContextId(self.0)
-    }
 }
 
 /// The type of fragment that a stacking context represents.