Make async XMLHttpRequest requests use async network events.

components/script/dom/bindings/cell.rs

@@ -16,6 +16,7 @@ use std::cell::{BorrowState, RefCell, Ref, RefMut};
 ///
 /// This extends the API of `core::cell::RefCell` to allow unsafe access in
 /// certain situations, with dynamic checking in debug builds.
+#[derive(Clone)]
 pub struct DOMRefCell<T> {
     value: RefCell<T>,
 }

components/script/dom/bindings/trace.rs

@@ -207,6 +207,16 @@ impl<T: JSTraceable> JSTraceable for Option<T> {
     }
 }
 
+impl<T: JSTraceable, U: JSTraceable> JSTraceable for Result<T, U> {
+    #[inline]
+    fn trace(&self, trc: *mut JSTracer) {
+        match *self {
+            Ok(ref inner) => inner.trace(trc),
+            Err(ref inner) => inner.trace(trc),
+        }
+    }
+}
+
 impl<K,V,S> JSTraceable for HashMap<K, V, S>
     where K: Hash + Eq + JSTraceable,
           V: JSTraceable,
@@ -297,6 +307,12 @@ impl JSTraceable for Box<LayoutRPC+'static> {
     }
 }
 
+impl JSTraceable for () {
+    #[inline]
+    fn trace(&self, _trc: *mut JSTracer) {
+    }
+}
+
 /// Holds a set of vectors that need to be rooted
 pub struct RootedCollectionSet {
     set: Vec<HashSet<*const RootedVec<()>>>