Update to latest rust-layers

The compositing context, painting context and display metadata have all
been collapsed into a single NativeDisplay class.

components/compositing/headless.rs

@@ -80,7 +80,7 @@ impl CompositorEventListener for NullCompositor {
                 return false
             }
 
-            Msg::GetGraphicsMetadata(chan) => {
+            Msg::GetNativeDisplay(chan) => {
                 chan.send(None).unwrap();
             }