Further changes required by Servo

components/atoms/static_atoms.txt

@@ -1,3 +1,4 @@
+-moz-gtk-csd-titlebar-radius
 DOMContentLoaded
 abort
 activate

components/style/servo/media_queries.rs

@@ -221,6 +221,12 @@ impl Device {
         }
     }
 
+    /// Returns the gtk titlebar radius in CSS pixels.
+    /// TODO: implement this method.
+    pub fn titlebar_radius(&self) -> f32 {
+        0.0
+    }
+
     /// Return whether the document is a chrome document.
     #[inline]
     pub fn is_chrome_document(&self) -> bool {