Ensure layout/script always have a correct viewport size when a new pipeline is created.

components/script/script_thread.rs

@@ -2392,6 +2392,7 @@ impl ScriptThread {
                 load_data.url.clone(),
             ),
             layout_is_busy: layout_is_busy.clone(),
+            window_size,
         });
 
         // Pick a layout thread, any layout thread