diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index 657ba4de11b..562135bb94b 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -678,6 +678,7 @@ impl<'le> TElement for GeckoElement<'le> {
         let atom_ptr = PseudoElement::ns_atom_or_null_from_opt(pseudo);
         unsafe {
             Gecko_UpdateAnimations(self.0, atom_ptr,
+                                   None,
                                    computed_values_opt,
                                    parent_values_opt,
                                    tasks.bits());
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index e65e3ce76c5..978a1ef8250 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -630,6 +630,8 @@ extern "C" {
 extern "C" {
     pub fn Gecko_UpdateAnimations(aElement: RawGeckoElementBorrowed,
                                   aPseudoTagOrNull: *mut nsIAtom,
+                                  aOldComputedValues:
+                                      ServoComputedValuesBorrowedOrNull,
                                   aComputedValues:
                                       ServoComputedValuesBorrowedOrNull,
                                   aParentComputedValues: