script: Expose NodeTraits::owner_global / Window::as_global_scope (#34843)

Expose two new helpers and start using them as much as possible.

- `NodeTraits::owner_global`: which gets the `GlobalScope` that currenty
 owns a `Node`. This may be different than `.global()` in the case that
 the `Node` was adopted by a different `Document`.
- `Window::as_global_scope`: A helper to avoid having to cast so much
  when treating a `Window` like a `GlobalScope`.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/dom/htmldetailselement.rs

@@ -82,16 +82,16 @@ impl VirtualMethods for HTMLDetailsElement {
             let counter = self.toggle_counter.get() + 1;
             self.toggle_counter.set(counter);
 
-            let window = self.owner_window();
             let this = Trusted::new(self);
-            window.task_manager().dom_manipulation_task_source().queue(
-                task!(details_notification_task_steps: move || {
+            self.owner_global()
+                .task_manager()
+                .dom_manipulation_task_source()
+                .queue(task!(details_notification_task_steps: move || {
                     let this = this.root();
                     if counter == this.toggle_counter.get() {
                         this.upcast::<EventTarget>().fire_event(atom!("toggle"), CanGc::note());
                     }
-                }),
-            );
+                }));
             self.upcast::<Node>().dirty(NodeDamage::OtherNodeDamage)
         }
     }