--- a/servo/components/style/invalidation/element/invalidator.rs
+++ b/servo/components/style/invalidation/element/invalidator.rs
@@ -234,17 +234,17 @@ impl<'a, 'b: 'a, E> TreeStyleInvalidator
         if sibling_invalidations.is_empty() {
             return false;
         }
 
         let mut current = self.element.next_sibling_element();
         let mut any_invalidated = false;
 
         while let Some(sibling) = current {
-            let mut sibling_data = sibling.get_data().map(|d| d.borrow_mut());
+            let mut sibling_data = sibling.mutate_data();
             let sibling_data = sibling_data.as_mut().map(|d| &mut **d);
 
             let mut sibling_invalidator = TreeStyleInvalidator::new(
                 sibling,
                 sibling_data,
                 self.shared_context
             );
 
@@ -297,17 +297,17 @@ impl<'a, 'b: 'a, E> TreeStyleInvalidator
 
         let mut any_children = false;
         for child in self.element.as_node().traversal_children() {
             let child = match child.as_element() {
                 Some(e) => e,
                 None => continue,
             };
 
-            let mut child_data = child.get_data().map(|d| d.borrow_mut());
+            let mut child_data = child.mutate_data();
             let child_data = child_data.as_mut().map(|d| &mut **d);
 
             let mut child_invalidator = TreeStyleInvalidator::new(
                 child,
                 child_data,
                 self.shared_context
             );