diff --git a/components/layout/animation.rs b/components/layout/animation.rs
index e4a2782c127..5d7a1a87acc 100644
--- a/components/layout/animation.rs
+++ b/components/layout/animation.rs
@@ -161,9 +161,7 @@ pub fn recalc_style_for_animations(context: &LayoutContext,
                                            &mut fragment.style,
                                            &ServoMetricsProvider);
                 let difference =
-                    RestyleDamage::compute_style_difference(&old_style,
-                                                            &old_style,
-                                                            &fragment.style);
+                    RestyleDamage::compute_style_difference(&old_style, &fragment.style);
                 damage |= difference.damage;
             }
         }
diff --git a/components/style/gecko/generated/bindings.rs b/components/style/gecko/generated/bindings.rs
index cc0989ddab1..93e7df0f4d0 100644
--- a/components/style/gecko/generated/bindings.rs
+++ b/components/style/gecko/generated/bindings.rs
@@ -1047,9 +1047,8 @@ extern "C" {
      -> CSSPseudoElementType;
 }
 extern "C" {
-    pub fn Gecko_CalcStyleDifference(old_style: *const ServoStyleContext,
-                                     new_style: *const ServoStyleContext,
-                                     old_style_bits: u64,
+    pub fn Gecko_CalcStyleDifference(oldstyle: *mut nsStyleContext,
+                                     newstyle: ServoComputedValuesBorrowed,
                                      any_style_changed: *mut bool)
      -> nsChangeHint;
 }
diff --git a/components/style/gecko/restyle_damage.rs b/components/style/gecko/restyle_damage.rs
index 62865e06b79..2af898a28aa 100644
--- a/components/style/gecko/restyle_damage.rs
+++ b/components/style/gecko/restyle_damage.rs
@@ -48,14 +48,14 @@ impl GeckoRestyleDamage {
     /// accessed from layout.
     pub fn compute_style_difference(
         source: &nsStyleContext,
-        old_style: &ComputedValues,
-        new_style: &Arc<ComputedValues>,
+        new_style: &Arc<ComputedValues>
     ) -> StyleDifference {
+        // TODO(emilio): Const-ify this?
+        let context = source as *const nsStyleContext as *mut nsStyleContext;
         let mut any_style_changed: bool = false;
         let hint = unsafe {
-            bindings::Gecko_CalcStyleDifference(old_style.as_style_context(),
-                                                new_style.as_style_context(),
-                                                source.mBits,
+            bindings::Gecko_CalcStyleDifference(context,
+                                                &new_style,
                                                 &mut any_style_changed)
         };
         let change = if any_style_changed { StyleChange::Changed } else { StyleChange::Unchanged };
diff --git a/components/style/matching.rs b/components/style/matching.rs
index 01c1fb53d1b..cc7d9415a1a 100644
--- a/components/style/matching.rs
+++ b/components/style/matching.rs
@@ -768,7 +768,7 @@ pub trait MatchMethods : TElement {
     ) -> StyleDifference {
         debug_assert!(pseudo.map_or(true, |p| p.is_eager()));
         if let Some(source) = self.existing_style_for_restyle_damage(old_values, pseudo) {
-            return RestyleDamage::compute_style_difference(source, old_values, new_values)
+            return RestyleDamage::compute_style_difference(source, new_values)
         }
 
         let new_display = new_values.get_box().clone_display();
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 4443f949eff..9a626f98c74 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -137,10 +137,6 @@ impl ComputedValues {
         let atom = Atom::from(atom);
         PseudoElement::from_atom(&atom)
     }
-
-    pub fn as_style_context(&self) -> &::gecko_bindings::structs::mozilla::ServoStyleContext {
-        &self.0
-    }
 }
 
 impl Drop for ComputedValues {
diff --git a/components/style/servo/restyle_damage.rs b/components/style/servo/restyle_damage.rs
index f85e8b6b13c..f99e6120bb9 100644
--- a/components/style/servo/restyle_damage.rs
+++ b/components/style/servo/restyle_damage.rs
@@ -60,8 +60,7 @@ impl HeapSizeOf for ServoRestyleDamage {
 impl ServoRestyleDamage {
     /// Compute the `StyleDifference` (including the appropriate restyle damage)
     /// for a given style change between `old` and `new`.
-    pub fn compute_style_difference(_source: &ComputedValues,
-                                    old: &ComputedValues,
+    pub fn compute_style_difference(old: &ComputedValues,
                                     new: &ComputedValues)
                                     -> StyleDifference {
         let damage = compute_damage(old, new);