diff --git a/components/style/media_queries.rs b/components/style/media_queries.rs
index d92dd324f99..9409b464f15 100644
--- a/components/style/media_queries.rs
+++ b/components/style/media_queries.rs
@@ -20,7 +20,7 @@ pub use servo::media_queries::{Device, Expression};
 pub use gecko::media_queries::{Device, Expression};
 
 /// A type that encapsulates a media query list.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct MediaList {
     /// The list of media queries.
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 4ef2f0ac43e..97f519cf0f7 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -1194,11 +1194,19 @@ pub extern "C" fn Servo_DeclarationBlock_RemovePropertyById(declarations: RawSer
 
 #[no_mangle]
 pub extern "C" fn Servo_MediaList_Create() -> RawServoMediaListStrong {
-
     let global_style_data = &*GLOBAL_STYLE_DATA;
     Arc::new(global_style_data.shared_lock.wrap(MediaList::default())).into_strong()
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_DeepClone(list: RawServoMediaListBorrowed) -> RawServoMediaListStrong {
+    let global_style_data = &*GLOBAL_STYLE_DATA;
+    read_locked_arc(list, |list: &MediaList| {
+        Arc::new(global_style_data.shared_lock.wrap(list.clone()))
+            .into_strong()
+    })
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_MediaList_Matches(list: RawServoMediaListBorrowed,
                                           raw_data: RawServoStyleSetBorrowed)