auto merge of #2649 : ebalint/servo/2580_JS_T_unrooted_replace, r=jdm

removed .clone() calls
modified from_rooted method parameter: T to &T

src/components/script/dom/attrlist.rs

@@ -20,8 +20,8 @@ impl AttrList {
     pub fn new_inherited(window: &JSRef<Window>, elem: &JSRef<Element>) -> AttrList {
         AttrList {
             reflector_: Reflector::new(),
-            window: window.unrooted(),
-            owner: elem.unrooted(),
+            window: JS::from_rooted(window),
+            owner: JS::from_rooted(elem),
         }
     }