nits

components/script/script_thread.rs

@@ -436,9 +436,10 @@ pub struct Documents {
 #[derive(JSTraceable)]
 #[crown::unrooted_must_root_lint::must_root]
 struct DocumentInfo {
+    /// The document associated with this pipeline.
+    document: Dom<Document>,
     /// The index of the last mouse move event in the pending compositor events queue.
     mouse_move_event_index: DomRefCell<Option<usize>>,
-    document: Dom<Document>,
     /// Pending animation ticks, to be handled at the next rendering opportunity.
     #[no_trace]
     pending_animation_ticks: DomRefCell<AnimationTickType>,
@@ -450,8 +451,8 @@ struct DocumentInfo {
 impl DocumentInfo {
     fn new(doc: &Document) -> DocumentInfo {
         DocumentInfo {
-            mouse_move_event_index: Default::default(),
             document: Dom::from_ref(doc),
+            mouse_move_event_index: Default::default(),
             pending_animation_ticks: Default::default(),
             pending_compositor_events: Default::default(),
         }
@@ -502,6 +503,7 @@ impl Documents {
                 CompositorEvent::MouseMoveEvent { .. } => {
                     let mut index = doc_info.mouse_move_event_index.borrow_mut();
                     if let Some(index) = *index {
+                        // Replace the pending mouse move event.
                         let mut pending_events = doc_info.pending_compositor_events.borrow_mut();
                         let mouse_move_event =
                             pending_events.get_mut(index).expect("index is valid");
@@ -1859,7 +1861,7 @@ impl ScriptThread {
             FromConstellation, FromDevtools, FromImageCache, FromScript, FromWebGPUServer,
         };
 
-        // Store new resizes, and gather all other events.
+        // Proritize rendering tasks and others, and gather all other events as `sequential`.
         let mut sequential = vec![];
 
         // Notify the background-hang-monitor we are waiting for an event.
@@ -2056,6 +2058,7 @@ impl ScriptThread {
             }
 
             // https://html.spec.whatwg.org/multipage/#event-loop-processing-model step 6
+            // TODO: only run after running a task(#32003).
             self.perform_a_microtask_checkpoint();
         }