servo: Merge #4490 - Remove some transmute calls (from Ms2ger:transmutes); r=jdm

Source-Repo: https://github.com/servo/servo
Source-Revision: dbb10747828b08f5dc9bcaea251e1f2d16f554fd

servo/components/layout/css/matching.rs

@@ -460,7 +460,7 @@ impl<'ln> PrivateMatchMethods for LayoutNode<'ln> {
         };
 
         let parent_layout_data: &Option<LayoutDataWrapper> = unsafe {
-            mem::transmute(parent_node.borrow_layout_data_unchecked())
+            &*parent_node.borrow_layout_data_unchecked()
         };
         match parent_layout_data {
             &Some(ref parent_layout_data_ref) => {

servo/components/script/dom/element.rs

@@ -226,8 +226,8 @@ pub trait RawLayoutElementHelpers {
 #[inline]
 unsafe fn get_attr_for_layout<'a>(elem: &'a Element, namespace: &Namespace, name: &Atom) -> Option<&'a JS<Attr>> {
     // cast to point to T in RefCell<T> directly
-    let attrs: *const Vec<JS<Attr>> = mem::transmute(&elem.attrs);
-    (*attrs).iter().find(|attr: & &JS<Attr>| {
+    let attrs = elem.attrs.borrow_for_layout();
+    attrs.iter().find(|attr: & &JS<Attr>| {
         let attr = attr.unsafe_get();
         *name == (*attr).local_name_atom_forever() &&
         (*attr).namespace() == namespace