diff --git a/components/script/layout_wrapper.rs b/components/script/layout_wrapper.rs
index 0875d437598..297ede7a564 100644
--- a/components/script/layout_wrapper.rs
+++ b/components/script/layout_wrapper.rs
@@ -187,12 +187,6 @@ impl<'ln> TNode for ServoLayoutNode<'ln> {
         self.children()
     }
 
-    fn children_and_traversal_children_might_differ(&self) -> bool {
-        // Servo doesn't have to worry about nodes being rearranged in the
-        // flattened tree like Gecko does (for XBL and Shadow DOM).  Yet.
-        false
-    }
-
     fn opaque(&self) -> OpaqueNode {
         unsafe { self.get_jsmanaged().opaque() }
     }
diff --git a/components/style/dom.rs b/components/style/dom.rs
index 29311727f16..27e2a9f75aa 100644
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@@ -127,10 +127,6 @@ pub trait TNode : Sized + Copy + Clone + Debug + NodeInfo {
     /// Get this node's children from the perspective of a restyle traversal.
     fn traversal_children(&self) -> LayoutIterator<Self::ConcreteChildrenIterator>;
 
-    /// Returns whether `children()` and `traversal_children()` might return
-    /// iterators over different nodes.
-    fn children_and_traversal_children_might_differ(&self) -> bool;
-
     /// Converts self into an `OpaqueNode`.
     fn opaque(&self) -> OpaqueNode;
 
diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index bfcbee65608..2394b11178b 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -275,13 +275,6 @@ impl<'ln> TNode for GeckoNode<'ln> {
         }
     }
 
-    fn children_and_traversal_children_might_differ(&self) -> bool {
-        match self.as_element() {
-            Some(e) => e.xbl_binding_anonymous_content().is_some(),
-            None => false,
-        }
-    }
-
     fn opaque(&self) -> OpaqueNode {
         let ptr: usize = self.0 as *const _ as usize;
         OpaqueNode(ptr)