script: Move `TaskManager` to `GlobalScope` (#34827)

This is a simplification of the internal `TaskQueue` API that moves the
`TaskManager` to the `GlobalScope` itself. In addition, the handling of
cancellers is moved to the `TaskManager` as well. This means that no
arguments other than the `task` are necessary for queueing tasks, which
makes the API a lot easier to use and cleaner.

`TaskSource` now also keeps a copy of the canceller with it, so that
they always know the proper way to cancel any tasks queued on them.

There is one complication here. The event loop `sender` for dedicated
workers is constantly changing as it is set to `None` when not handling
messages. This is because this sender keeps a handle to the main
thread's `Worker` object, preventing garbage collection while any
messages are still in flight or being handled. This change allows
setting the `sender` on the `TaskManager` to `None` to allow proper
garbabge collection.

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

1 files changed, 7 insertions, 9 deletions

diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index f970d351d35..18f67c5d86c 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -152,7 +152,6 @@ use crate::script_runtime::{
     CanGc, CommonScriptMsg, JSContext, Runtime, ScriptChan, ScriptThreadEventCategory,
     ThreadSafeJSContext,
 };
-use crate::task_manager::TaskManager;
 use crate::task_queue::TaskQueue;
 use crate::task_source::{TaskSource, TaskSourceName};
 use crate::{devtools, webdriver_handlers};
@@ -693,7 +692,7 @@ impl ScriptThread {
                 global
                     .task_manager()
                     .dom_manipulation_task_source()
-                    .queue(task, global.upcast())
+                    .queue(task)
                     .expect("Enqueing navigate js task on the DOM manipulation task source failed");
             } else {
                 if let Some(ref sender) = script_thread.senders.devtools_server_sender {
@@ -907,6 +906,7 @@ impl ScriptThread {
             sender: self_sender.as_boxed(),
             pipeline_id: state.id,
             name: TaskSourceName::Networking,
+            canceller: Default::default(),
         }));
         let cx = runtime.cx();
 
@@ -1033,8 +1033,10 @@ impl ScriptThread {
     fn prepare_for_shutdown_inner(&self) {
         let docs = self.documents.borrow();
         for (_, document) in docs.iter() {
-            let window = document.window();
-            window.ignore_all_tasks();
+            document
+                .window()
+                .task_manager()
+                .cancel_all_tasks_and_ignore_future_tasks();
         }
     }
 
@@ -1407,6 +1409,7 @@ impl ScriptThread {
         //
         // This task is empty because any new IPC messages in the ScriptThread trigger a
         // rendering update when animations are not running.
+        let _realm = enter_realm(&*document);
         let rendering_task_source = document.window().task_manager().rendering_task_source();
         let _ =
             rendering_task_source.queue_unconditionally(task!(update_the_rendering: move || { }));
@@ -3129,10 +3132,6 @@ impl ScriptThread {
             pipeline_id: incomplete.pipeline_id,
         };
 
-        let task_manager = TaskManager::new(
-            Box::new(self.senders.self_sender.clone()),
-            incomplete.pipeline_id,
-        );
         let paint_time_metrics = PaintTimeMetrics::new(
             incomplete.pipeline_id,
             self.senders.time_profiler_sender.clone(),
@@ -3161,7 +3160,6 @@ impl ScriptThread {
         let window = Window::new(
             self.js_runtime.clone(),
             self.senders.self_sender.clone(),
-            task_manager,
             self.layout_factory.create(layout_config),
             self.senders.image_cache_sender.clone(),
             self.image_cache.clone(),