script: Refactor channels in ScriptThread into receivers and senders (#34776)

Create two new data structures in the `script` crate to hold senders and
receiver:

- `ScriptThreadSenders`: holds all outgoing channels from the
  `ScriptThread` including a channel to the `ScriptThread` itself. The
  ultimate goal with this is to reduce duplication by giving a boxed
  version of this this to `Window`s.
- `ScriptThradReceivers`: holds all incoming channels to the
  `ScriptThread`. This isn't cloenable like the senders. This is used to
  abstract away `recv()` and `try_recv()` methods used to make the
  `ScriptThread` event loop easier to read.

In addition:

- The many duplicated `ScriptThread` self-senders for the `TaskManager`
  have been removed and, in general, a lot of boilerplate is removed as
  well.
- Visibilty of all methods affected by this change is changed to
  `pub(crate)` in order to take advantage of dead code detection. Some
  dead code produced from macros is removed.
- Some conversion code is refactord into implementations of the `From`
  trait.
- The names of channels uses a standard "sender" and "receiver" naming
  as well as trying to be descriptive of where they go in `ScriptThread`
  as well as `InitialScriptState`

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

components/constellation/pipeline.rs

@@ -518,20 +518,20 @@ impl UnprivilegedPipelineContent {
                 top_level_browsing_context_id: self.top_level_browsing_context_id,
                 parent_info: self.parent_pipeline_id,
                 opener: self.opener,
-                control_chan: self.script_chan.clone(),
+                constellation_sender: self.script_chan.clone(),
-                control_port: self.script_port,
+                constellation_receiver: self.script_port,
-                script_to_constellation_chan: self.script_to_constellation_chan.clone(),
+                pipeline_to_constellation_sender: self.script_to_constellation_chan.clone(),
                 background_hang_monitor_register: background_hang_monitor_register.clone(),
-                layout_to_constellation_chan: self.layout_to_constellation_chan.clone(),
+                layout_to_constellation_ipc_sender: self.layout_to_constellation_chan.clone(),
-                bluetooth_thread: self.bluetooth_thread,
+                bluetooth_sender: self.bluetooth_thread,
                 resource_threads: self.resource_threads,
                 image_cache: image_cache.clone(),
-                time_profiler_chan: self.time_profiler_chan.clone(),
+                time_profiler_sender: self.time_profiler_chan.clone(),
-                mem_profiler_chan: self.mem_profiler_chan.clone(),
+                memory_profiler_sender: self.mem_profiler_chan.clone(),
-                devtools_chan: self.devtools_ipc_sender,
+                devtools_server_sender: self.devtools_ipc_sender,
                 window_size: self.window_size,
                 pipeline_namespace_id: self.pipeline_namespace_id,
-                content_process_shutdown_chan,
+                content_process_shutdown_sender: content_process_shutdown_chan,
                 webgl_chan: self.webgl_chan,
                 webxr_registry: self.webxr_registry,
                 webrender_document: self.webrender_document,

components/script/dom/abstractworkerglobalscope.rs

@@ -35,7 +35,7 @@ impl ScriptChan for SendableWorkerScriptChan {
         self.sender.send(msg).map_err(|_| ())
     }
 
-    fn clone(&self) -> Box<dyn ScriptChan + Send> {
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send> {
         Box::new(SendableWorkerScriptChan {
             sender: self.sender.clone(),
             worker: self.worker.clone(),
@@ -62,7 +62,7 @@ impl ScriptChan for WorkerThreadWorkerChan {
         self.sender.send(msg).map_err(|_| ())
     }
 
-    fn clone(&self) -> Box<dyn ScriptChan + Send> {
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send> {
         Box::new(WorkerThreadWorkerChan {
             sender: self.sender.clone(),
             worker: self.worker.clone(),

components/script/dom/dedicatedworkerglobalscope.rs

@@ -418,7 +418,7 @@ impl DedicatedWorkerGlobalScope {
                     worker_url,
                     devtools_mpsc_port,
                     runtime,
-                    parent_sender.clone(),
+                    parent_sender.as_boxed(),
                     own_sender,
                     receiver,
                     closing,

components/script/dom/document.rs

@@ -185,10 +185,11 @@ use crate::dom::windowproxy::WindowProxy;
 use crate::dom::xpathevaluator::XPathEvaluator;
 use crate::fetch::FetchCanceller;
 use crate::iframe_collection::IFrameCollection;
+use crate::messaging::MainThreadScriptMsg;
 use crate::network_listener::{NetworkListener, PreInvoke};
 use crate::realms::{enter_realm, AlreadyInRealm, InRealm};
 use crate::script_runtime::{CanGc, CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::{with_script_thread, MainThreadScriptMsg, ScriptThread};
+use crate::script_thread::{with_script_thread, ScriptThread};
 use crate::stylesheet_set::StylesheetSetRef;
 use crate::task::TaskBox;
 use crate::task_source::{TaskSource, TaskSourceName};

components/script/dom/globalscope.rs

@@ -127,6 +127,7 @@ use crate::dom::webgpu::identityhub::IdentityHub;
 use crate::dom::window::Window;
 use crate::dom::workerglobalscope::WorkerGlobalScope;
 use crate::dom::workletglobalscope::WorkletGlobalScope;
+use crate::messaging::MainThreadScriptChan;
 use crate::microtask::{Microtask, MicrotaskQueue, UserMicrotask};
 use crate::network_listener::{NetworkListener, PreInvoke};
 use crate::realms::{enter_realm, AlreadyInRealm, InRealm};
@@ -134,7 +135,7 @@ use crate::script_module::{DynamicModuleList, ModuleScript, ModuleTree, ScriptFe
 use crate::script_runtime::{
     CanGc, CommonScriptMsg, JSContext as SafeJSContext, ScriptChan, ScriptPort, ThreadSafeJSContext,
 };
-use crate::script_thread::{with_script_thread, MainThreadScriptChan, ScriptThread};
+use crate::script_thread::{with_script_thread, ScriptThread};
 use crate::security_manager::CSPViolationReporter;
 use crate::task::TaskCanceller;
 use crate::task_source::dom_manipulation::DOMManipulationTaskSource;
@@ -2581,7 +2582,9 @@ impl GlobalScope {
     /// `ScriptChan` to send messages to the event loop of this global scope.
     pub fn script_chan(&self) -> Box<dyn ScriptChan + Send> {
         if let Some(window) = self.downcast::<Window>() {
-            return MainThreadScriptChan(window.main_thread_script_chan().clone()).clone();
+            return Box::new(
+                MainThreadScriptChan(window.main_thread_script_chan().clone()).clone(),
+            );
         }
         if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
             return worker.script_chan();

components/script/dom/paintworkletglobalscope.rs

@@ -86,7 +86,7 @@ pub struct PaintWorkletGlobalScope {
 
 impl PaintWorkletGlobalScope {
     #[allow(unsafe_code)]
-    pub fn new(
+    pub(crate) fn new(
         runtime: &Runtime,
         pipeline_id: PipelineId,
         base_url: ServoUrl,

components/script/dom/serviceworkerglobalscope.rs

@@ -143,7 +143,7 @@ impl ScriptChan for ServiceWorkerChan {
             .map_err(|_| ())
     }
 
-    fn clone(&self) -> Box<dyn ScriptChan + Send> {
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send> {
         Box::new(ServiceWorkerChan {
             sender: self.sender.clone(),
         })

components/script/dom/testworkletglobalscope.rs

@@ -31,7 +31,7 @@ pub struct TestWorkletGlobalScope {
 
 impl TestWorkletGlobalScope {
     #[allow(unsafe_code)]
-    pub fn new(
+    pub(crate) fn new(
         runtime: &Runtime,
         pipeline_id: PipelineId,
         base_url: ServoUrl,

components/script/dom/window.rs

@@ -145,15 +145,15 @@ use crate::dom::windowproxy::{WindowProxy, WindowProxyHandler};
 use crate::dom::worklet::Worklet;
 use crate::dom::workletglobalscope::WorkletGlobalScopeType;
 use crate::layout_image::fetch_image_for_layout;
+use crate::messaging::{
+    ImageCacheMsg, MainThreadScriptChan, MainThreadScriptMsg, SendableMainThreadScriptChan,
+};
 use crate::microtask::MicrotaskQueue;
 use crate::realms::{enter_realm, InRealm};
 use crate::script_runtime::{
     CanGc, CommonScriptMsg, JSContext, Runtime, ScriptChan, ScriptPort, ScriptThreadEventCategory,
 };
-use crate::script_thread::{
+use crate::script_thread::ScriptThread;
-    ImageCacheMsg, MainThreadScriptChan, MainThreadScriptMsg, ScriptThread,
-    SendableMainThreadScriptChan,
-};
 use crate::task_manager::TaskManager;
 use crate::task_source::{TaskSource, TaskSourceName};
 use crate::timers::{IsInterval, TimerCallback};
@@ -453,7 +453,7 @@ impl Window {
         self.js_runtime.borrow()
     }
 
-    pub fn main_thread_script_chan(&self) -> &Sender<MainThreadScriptMsg> {
+    pub(crate) fn main_thread_script_chan(&self) -> &Sender<MainThreadScriptMsg> {
         &self.script_chan.0
     }
 
@@ -2683,7 +2683,7 @@ impl Window {
 impl Window {
     #[allow(unsafe_code)]
     #[allow(clippy::too_many_arguments)]
-    pub fn new(
+    pub(crate) fn new(
         runtime: Rc<Runtime>,
         script_chan: MainThreadScriptChan,
         task_manager: TaskManager,

components/script/dom/worklet.rs

@@ -49,9 +49,10 @@ use crate::dom::workletglobalscope::{
     WorkletGlobalScope, WorkletGlobalScopeInit, WorkletGlobalScopeType, WorkletTask,
 };
 use crate::fetch::load_whole_resource;
+use crate::messaging::MainThreadScriptMsg;
 use crate::realms::InRealm;
 use crate::script_runtime::{CanGc, CommonScriptMsg, Runtime, ScriptThreadEventCategory};
-use crate::script_thread::{MainThreadScriptMsg, ScriptThread};
+use crate::script_thread::ScriptThread;
 use crate::task::TaskBox;
 use crate::task_source::TaskSourceName;
 
@@ -277,7 +278,7 @@ impl Drop for WorkletThreadPool {
 impl WorkletThreadPool {
     /// Create a new thread pool and spawn the threads.
     /// When the thread pool is dropped, the threads will be asked to quit.
-    pub fn spawn(global_init: WorkletGlobalScopeInit) -> WorkletThreadPool {
+    pub(crate) fn spawn(global_init: WorkletGlobalScopeInit) -> WorkletThreadPool {
         let primary_role = WorkletThreadRole::new(false, false);
         let hot_backup_role = WorkletThreadRole::new(true, false);
         let cold_backup_role = WorkletThreadRole::new(false, true);

components/script/dom/workletglobalscope.rs

@@ -27,9 +27,9 @@ use crate::dom::testworkletglobalscope::{TestWorkletGlobalScope, TestWorkletTask
 #[cfg(feature = "webgpu")]
 use crate::dom::webgpu::identityhub::IdentityHub;
 use crate::dom::worklet::WorkletExecutor;
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_module::ScriptFetchOptions;
 use crate::script_runtime::{CanGc, JSContext};
-use crate::script_thread::MainThreadScriptMsg;
 
 #[dom_struct]
 /// <https://drafts.css-houdini.org/worklets/#workletglobalscope>
@@ -49,7 +49,7 @@ pub struct WorkletGlobalScope {
 
 impl WorkletGlobalScope {
     /// Create a new heap-allocated `WorkletGlobalScope`.
-    pub fn new(
+    pub(crate) fn new(
         scope_type: WorkletGlobalScopeType,
         runtime: &Runtime,
         pipeline_id: PipelineId,
@@ -76,7 +76,7 @@ impl WorkletGlobalScope {
     }
 
     /// Create a new stack-allocated `WorkletGlobalScope`.
-    pub fn new_inherited(
+    pub(crate) fn new_inherited(
         pipeline_id: PipelineId,
         base_url: ServoUrl,
         executor: WorkletExecutor,
@@ -172,7 +172,7 @@ impl WorkletGlobalScope {
 
 /// Resources required by workletglobalscopes
 #[derive(Clone)]
-pub struct WorkletGlobalScopeInit {
+pub(crate) struct WorkletGlobalScopeInit {
     /// Channel to the main script thread
     pub to_script_thread_sender: Sender<MainThreadScriptMsg>,
     /// Channel to a resource thread

components/script/lib.rs

@@ -61,6 +61,9 @@ pub mod layout_dom;
 #[warn(deprecated)]
 mod mem;
 #[warn(deprecated)]
+#[allow(unsafe_code)]
+pub mod messaging;
+#[warn(deprecated)]
 mod microtask;
 #[warn(deprecated)]
 mod network_listener;

components/script/messaging.rs

@@ -0,0 +1,398 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::cell::RefCell;
+use std::option::Option;
+use std::result::Result;
+
+use base::id::PipelineId;
+use bluetooth_traits::BluetoothRequest;
+use crossbeam_channel::{select, Receiver, Sender};
+use devtools_traits::{DevtoolScriptControlMsg, ScriptToDevtoolsControlMsg};
+use ipc_channel::ipc::IpcSender;
+use net_traits::image_cache::PendingImageResponse;
+use profile_traits::mem::{self as profile_mem, OpaqueSender};
+use profile_traits::time::{self as profile_time};
+use script_traits::{ConstellationControlMsg, LayoutMsg, Painter, ScriptMsg};
+use servo_atoms::Atom;
+use timers::TimerScheduler;
+#[cfg(feature = "webgpu")]
+use webgpu::WebGPUMsg;
+
+use crate::dom::serviceworker::TrustedServiceWorkerAddress;
+use crate::dom::worker::TrustedWorkerAddress;
+use crate::script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort};
+use crate::task_queue::{QueuedTask, QueuedTaskConversion, TaskQueue};
+use crate::task_source::TaskSourceName;
+
+pub(crate) type ImageCacheMsg = (PipelineId, PendingImageResponse);
+
+#[derive(Debug)]
+pub(crate) enum MixedMessage {
+    FromConstellation(ConstellationControlMsg),
+    FromScript(MainThreadScriptMsg),
+    FromDevtools(DevtoolScriptControlMsg),
+    FromImageCache((PipelineId, PendingImageResponse)),
+    #[cfg(feature = "webgpu")]
+    FromWebGPUServer(WebGPUMsg),
+    TimerFired,
+}
+
+impl MixedMessage {
+    pub(crate) fn pipeline_id(&self) -> Option<PipelineId> {
+        match self {
+            MixedMessage::FromConstellation(ref inner_msg) => match *inner_msg {
+                ConstellationControlMsg::StopDelayingLoadEventsMode(id) => Some(id),
+                ConstellationControlMsg::NavigationResponse(id, _) => Some(id),
+                ConstellationControlMsg::AttachLayout(ref new_layout_info) => new_layout_info
+                    .parent_info
+                    .or(Some(new_layout_info.new_pipeline_id)),
+                ConstellationControlMsg::Resize(id, ..) => Some(id),
+                ConstellationControlMsg::ThemeChange(id, ..) => Some(id),
+                ConstellationControlMsg::ResizeInactive(id, ..) => Some(id),
+                ConstellationControlMsg::UnloadDocument(id) => Some(id),
+                ConstellationControlMsg::ExitPipeline(id, ..) => Some(id),
+                ConstellationControlMsg::ExitScriptThread => None,
+                ConstellationControlMsg::SendEvent(id, ..) => Some(id),
+                ConstellationControlMsg::Viewport(id, ..) => Some(id),
+                ConstellationControlMsg::GetTitle(id) => Some(id),
+                ConstellationControlMsg::SetDocumentActivity(id, ..) => Some(id),
+                ConstellationControlMsg::SetThrottled(id, ..) => Some(id),
+                ConstellationControlMsg::SetThrottledInContainingIframe(id, ..) => Some(id),
+                ConstellationControlMsg::NavigateIframe(id, ..) => Some(id),
+                ConstellationControlMsg::PostMessage { target: id, .. } => Some(id),
+                ConstellationControlMsg::UpdatePipelineId(_, _, _, id, _) => Some(id),
+                ConstellationControlMsg::UpdateHistoryState(id, ..) => Some(id),
+                ConstellationControlMsg::RemoveHistoryStates(id, ..) => Some(id),
+                ConstellationControlMsg::FocusIFrame(id, ..) => Some(id),
+                ConstellationControlMsg::WebDriverScriptCommand(id, ..) => Some(id),
+                ConstellationControlMsg::TickAllAnimations(id, ..) => Some(id),
+                ConstellationControlMsg::WebFontLoaded(id, ..) => Some(id),
+                ConstellationControlMsg::DispatchIFrameLoadEvent {
+                    target: _,
+                    parent: id,
+                    child: _,
+                } => Some(id),
+                ConstellationControlMsg::DispatchStorageEvent(id, ..) => Some(id),
+                ConstellationControlMsg::ReportCSSError(id, ..) => Some(id),
+                ConstellationControlMsg::Reload(id, ..) => Some(id),
+                ConstellationControlMsg::PaintMetric(id, ..) => Some(id),
+                ConstellationControlMsg::ExitFullScreen(id, ..) => Some(id),
+                ConstellationControlMsg::MediaSessionAction(..) => None,
+                #[cfg(feature = "webgpu")]
+                ConstellationControlMsg::SetWebGPUPort(..) => None,
+                ConstellationControlMsg::SetScrollStates(id, ..) => Some(id),
+                ConstellationControlMsg::SetEpochPaintTime(id, ..) => Some(id),
+            },
+            MixedMessage::FromScript(ref inner_msg) => match *inner_msg {
+                MainThreadScriptMsg::Common(CommonScriptMsg::Task(_, _, pipeline_id, _)) => {
+                    pipeline_id
+                },
+                MainThreadScriptMsg::Common(CommonScriptMsg::CollectReports(_)) => None,
+                MainThreadScriptMsg::WorkletLoaded(pipeline_id) => Some(pipeline_id),
+                MainThreadScriptMsg::RegisterPaintWorklet { pipeline_id, .. } => Some(pipeline_id),
+                MainThreadScriptMsg::Inactive => None,
+                MainThreadScriptMsg::WakeUp => None,
+            },
+            MixedMessage::FromImageCache((pipeline_id, _)) => Some(*pipeline_id),
+            MixedMessage::FromDevtools(_) | MixedMessage::TimerFired => None,
+            #[cfg(feature = "webgpu")]
+            MixedMessage::FromWebGPUServer(..) => None,
+        }
+    }
+}
+
+/// Messages used to control the script event loop.
+#[derive(Debug)]
+pub(crate) enum MainThreadScriptMsg {
+    /// Common variants associated with the script messages
+    Common(CommonScriptMsg),
+    /// Notifies the script thread that a new worklet has been loaded, and thus the page should be
+    /// reflowed.
+    WorkletLoaded(PipelineId),
+    /// Notifies the script thread that a new paint worklet has been registered.
+    RegisterPaintWorklet {
+        pipeline_id: PipelineId,
+        name: Atom,
+        properties: Vec<Atom>,
+        painter: Box<dyn Painter>,
+    },
+    /// A task related to a not fully-active document has been throttled.
+    Inactive,
+    /// Wake-up call from the task queue.
+    WakeUp,
+}
+
+impl QueuedTaskConversion for MainThreadScriptMsg {
+    fn task_source_name(&self) -> Option<&TaskSourceName> {
+        let script_msg = match self {
+            MainThreadScriptMsg::Common(script_msg) => script_msg,
+            _ => return None,
+        };
+        match script_msg {
+            CommonScriptMsg::Task(_category, _boxed, _pipeline_id, task_source) => {
+                Some(task_source)
+            },
+            _ => None,
+        }
+    }
+
+    fn pipeline_id(&self) -> Option<PipelineId> {
+        let script_msg = match self {
+            MainThreadScriptMsg::Common(script_msg) => script_msg,
+            _ => return None,
+        };
+        match script_msg {
+            CommonScriptMsg::Task(_category, _boxed, pipeline_id, _task_source) => *pipeline_id,
+            _ => None,
+        }
+    }
+
+    fn into_queued_task(self) -> Option<QueuedTask> {
+        let script_msg = match self {
+            MainThreadScriptMsg::Common(script_msg) => script_msg,
+            _ => return None,
+        };
+        let (category, boxed, pipeline_id, task_source) = match script_msg {
+            CommonScriptMsg::Task(category, boxed, pipeline_id, task_source) => {
+                (category, boxed, pipeline_id, task_source)
+            },
+            _ => return None,
+        };
+        Some((None, category, boxed, pipeline_id, task_source))
+    }
+
+    fn from_queued_task(queued_task: QueuedTask) -> Self {
+        let (_worker, category, boxed, pipeline_id, task_source) = queued_task;
+        let script_msg = CommonScriptMsg::Task(category, boxed, pipeline_id, task_source);
+        MainThreadScriptMsg::Common(script_msg)
+    }
+
+    fn inactive_msg() -> Self {
+        MainThreadScriptMsg::Inactive
+    }
+
+    fn wake_up_msg() -> Self {
+        MainThreadScriptMsg::WakeUp
+    }
+
+    fn is_wake_up(&self) -> bool {
+        matches!(self, MainThreadScriptMsg::WakeUp)
+    }
+}
+
+impl OpaqueSender<CommonScriptMsg> for Box<dyn ScriptChan + Send> {
+    fn send(&self, msg: CommonScriptMsg) {
+        ScriptChan::send(&**self, msg).unwrap();
+    }
+}
+
+impl ScriptPort for Receiver<CommonScriptMsg> {
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        self.recv().map_err(|_| ())
+    }
+}
+
+impl ScriptPort for Receiver<MainThreadScriptMsg> {
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        match self.recv() {
+            Ok(MainThreadScriptMsg::Common(script_msg)) => Ok(script_msg),
+            Ok(_) => panic!("unexpected main thread event message!"),
+            Err(_) => Err(()),
+        }
+    }
+}
+
+impl ScriptPort for Receiver<(TrustedWorkerAddress, CommonScriptMsg)> {
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        self.recv().map(|(_, msg)| msg).map_err(|_| ())
+    }
+}
+
+impl ScriptPort for Receiver<(TrustedWorkerAddress, MainThreadScriptMsg)> {
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        match self.recv().map(|(_, msg)| msg) {
+            Ok(MainThreadScriptMsg::Common(script_msg)) => Ok(script_msg),
+            Ok(_) => panic!("unexpected main thread event message!"),
+            Err(_) => Err(()),
+        }
+    }
+}
+
+impl ScriptPort for Receiver<(TrustedServiceWorkerAddress, CommonScriptMsg)> {
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        self.recv().map(|(_, msg)| msg).map_err(|_| ())
+    }
+}
+
+/// Encapsulates internal communication of shared messages within the script thread.
+#[derive(Clone, JSTraceable)]
+pub(crate) struct SendableMainThreadScriptChan(#[no_trace] pub Sender<CommonScriptMsg>);
+
+impl ScriptChan for SendableMainThreadScriptChan {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
+        self.0.send(msg).map_err(|_| ())
+    }
+
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send> {
+        Box::new(SendableMainThreadScriptChan((self.0).clone()))
+    }
+}
+
+/// Encapsulates internal communication of main thread messages within the script thread.
+#[derive(Clone, JSTraceable)]
+pub(crate) struct MainThreadScriptChan(#[no_trace] pub Sender<MainThreadScriptMsg>);
+
+impl ScriptChan for MainThreadScriptChan {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
+        self.0
+            .send(MainThreadScriptMsg::Common(msg))
+            .map_err(|_| ())
+    }
+
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send> {
+        Box::new(MainThreadScriptChan((self.0).clone()))
+    }
+}
+
+impl OpaqueSender<CommonScriptMsg> for Sender<MainThreadScriptMsg> {
+    fn send(&self, msg: CommonScriptMsg) {
+        self.send(MainThreadScriptMsg::Common(msg)).unwrap()
+    }
+}
+
+#[derive(Clone, JSTraceable)]
+pub(crate) struct ScriptThreadSenders {
+    /// A channel to hand out to script thread-based entities that need to be able to enqueue
+    /// events in the event queue.
+    pub self_sender: MainThreadScriptChan,
+
+    /// A handle to the bluetooth thread.
+    #[no_trace]
+    pub bluetooth_sender: IpcSender<BluetoothRequest>,
+
+    /// A [`Sender`] that sends messages to the `Constellation`.
+    #[no_trace]
+    pub constellation_sender: IpcSender<ConstellationControlMsg>,
+
+    /// A [`Sender`] that sends messages to the `Constellation` associated with
+    /// particular pipelines.
+    #[no_trace]
+    pub pipeline_to_constellation_sender: IpcSender<(PipelineId, ScriptMsg)>,
+
+    /// A sender for layout to communicate to the constellation.
+    #[no_trace]
+    pub layout_to_constellation_ipc_sender: IpcSender<LayoutMsg>,
+
+    /// The [`Sender`] on which messages can be sent to the `ImageCache`.
+    #[no_trace]
+    pub image_cache_sender: Sender<ImageCacheMsg>,
+
+    /// For providing contact with the time profiler.
+    #[no_trace]
+    pub time_profiler_sender: profile_time::ProfilerChan,
+
+    /// For providing contact with the memory profiler.
+    #[no_trace]
+    pub memory_profiler_sender: profile_mem::ProfilerChan,
+
+    /// For providing instructions to an optional devtools server.
+    #[no_trace]
+    pub devtools_server_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
+
+    #[no_trace]
+    pub devtools_client_to_script_thread_sender: IpcSender<DevtoolScriptControlMsg>,
+
+    #[no_trace]
+    pub content_process_shutdown_sender: Sender<()>,
+}
+
+#[derive(JSTraceable)]
+pub(crate) struct ScriptThreadReceivers {
+    /// A [`Receiver`] that receives messages from the constellation.
+    #[no_trace]
+    pub constellation_receiver: Receiver<ConstellationControlMsg>,
+
+    /// The [`Receiver`] which receives incoming messages from the `ImageCache`.
+    #[no_trace]
+    pub image_cache_receiver: Receiver<ImageCacheMsg>,
+
+    /// For receiving commands from an optional devtools server. Will be ignored if
+    /// no such server exists.
+    #[no_trace]
+    pub devtools_server_receiver: Receiver<DevtoolScriptControlMsg>,
+
+    /// Receiver to receive commands from optional WebGPU server.
+    #[no_trace]
+    #[cfg(feature = "webgpu")]
+    pub webgpu_receiver: RefCell<Receiver<WebGPUMsg>>,
+}
+
+impl ScriptThreadReceivers {
+    /// Block until a message is received by any of the receivers of this [`ScriptThreadReceivers`]
+    /// or the given [`TaskQueue`] or [`TimerScheduler`]. Return the first message received.
+    pub(crate) fn recv(
+        &self,
+        task_queue: &TaskQueue<MainThreadScriptMsg>,
+        timer_scheduler: &TimerScheduler,
+    ) -> MixedMessage {
+        select! {
+            recv(task_queue.select()) -> msg => {
+                task_queue.take_tasks(msg.unwrap());
+                let event = task_queue
+                    .recv()
+                    .expect("Spurious wake-up of the event-loop, task-queue has no tasks available");
+                MixedMessage::FromScript(event)
+            },
+            recv(self.constellation_receiver) -> msg => MixedMessage::FromConstellation(msg.unwrap()),
+            recv(self.devtools_server_receiver) -> msg => MixedMessage::FromDevtools(msg.unwrap()),
+            recv(self.image_cache_receiver) -> msg => MixedMessage::FromImageCache(msg.unwrap()),
+            recv(timer_scheduler.wait_channel()) -> _ => MixedMessage::TimerFired,
+            recv({
+                #[cfg(feature = "webgpu")]
+                {
+                    self.webgpu_receiver.borrow()
+                }
+                #[cfg(not(feature = "webgpu"))]
+                {
+                    &crossbeam_channel::never::<()>()
+                }
+            }) -> msg => {
+                #[cfg(feature = "webgpu")]
+                {
+                    MixedMessage::FromWebGPUServer(msg.unwrap())
+                }
+                #[cfg(not(feature = "webgpu"))]
+                {
+                    unreachable!("This should never be hit when webgpu is disabled");
+                }
+            }
+        }
+    }
+
+    /// Try to receive a from any of the receivers of this [`ScriptThreadReceivers`] or the given
+    /// [`TaskQueue`]. Return `None` if no messages are ready to be received.
+    pub(crate) fn try_recv(
+        &self,
+        task_queue: &TaskQueue<MainThreadScriptMsg>,
+    ) -> Option<MixedMessage> {
+        if let Ok(message) = self.constellation_receiver.try_recv() {
+            return MixedMessage::FromConstellation(message).into();
+        }
+        if let Ok(message) = task_queue.take_tasks_and_recv() {
+            return MixedMessage::FromScript(message).into();
+        }
+        if let Ok(message) = self.devtools_server_receiver.try_recv() {
+            return MixedMessage::FromDevtools(message).into();
+        }
+        if let Ok(message) = self.image_cache_receiver.try_recv() {
+            return MixedMessage::FromImageCache(message).into();
+        }
+        #[cfg(feature = "webgpu")]
+        if let Ok(message) = self.webgpu_receiver.borrow().try_recv() {
+            return MixedMessage::FromWebGPUServer(message).into();
+        }
+        None
+    }
+}

components/script/script_runtime.rs

@@ -18,6 +18,7 @@ use std::sync::Mutex;
 use std::time::{Duration, Instant};
 use std::{fmt, os, ptr, thread};
 
+use background_hang_monitor_api::ScriptHangAnnotation;
 use base::id::PipelineId;
 use content_security_policy::{CheckResult, PolicyDisposition};
 use js::conversions::jsstr_to_string;
@@ -50,6 +51,7 @@ use js::rust::{
 use malloc_size_of::MallocSizeOfOps;
 use profile_traits::mem::{Report, ReportKind, ReportsChan};
 use profile_traits::path;
+use profile_traits::time::ProfilerCategory;
 use servo_config::{opts, pref};
 use style::thread_state::{self, ThreadState};
 
@@ -126,8 +128,8 @@ pub trait ScriptChan: JSTraceable {
     /// Send a message to the associated event loop.
     #[allow(clippy::result_unit_err)]
     fn send(&self, msg: CommonScriptMsg) -> Result<(), ()>;
-    /// Clone this handle.
+    /// Return a cloned version of this sender in a [`Box`].
-    fn clone(&self) -> Box<dyn ScriptChan + Send>;
+    fn as_boxed(&self) -> Box<dyn ScriptChan + Send>;
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, JSTraceable, PartialEq)]
@@ -162,6 +164,92 @@ pub enum ScriptThreadEventCategory {
     WebGPUMsg,
 }
 
+impl From<ScriptThreadEventCategory> for ProfilerCategory {
+    fn from(category: ScriptThreadEventCategory) -> Self {
+        match category {
+            ScriptThreadEventCategory::AttachLayout => ProfilerCategory::ScriptAttachLayout,
+            ScriptThreadEventCategory::ConstellationMsg => ProfilerCategory::ScriptConstellationMsg,
+            ScriptThreadEventCategory::DevtoolsMsg => ProfilerCategory::ScriptDevtoolsMsg,
+            ScriptThreadEventCategory::DocumentEvent => ProfilerCategory::ScriptDocumentEvent,
+            ScriptThreadEventCategory::DomEvent => ProfilerCategory::ScriptDomEvent,
+            ScriptThreadEventCategory::EnterFullscreen => ProfilerCategory::ScriptEnterFullscreen,
+            ScriptThreadEventCategory::ExitFullscreen => ProfilerCategory::ScriptExitFullscreen,
+            ScriptThreadEventCategory::FileRead => ProfilerCategory::ScriptFileRead,
+            ScriptThreadEventCategory::FormPlannedNavigation => {
+                ProfilerCategory::ScriptPlannedNavigation
+            },
+            ScriptThreadEventCategory::HistoryEvent => ProfilerCategory::ScriptHistoryEvent,
+            ScriptThreadEventCategory::ImageCacheMsg => ProfilerCategory::ScriptImageCacheMsg,
+            ScriptThreadEventCategory::InputEvent => ProfilerCategory::ScriptInputEvent,
+            ScriptThreadEventCategory::NetworkEvent => ProfilerCategory::ScriptNetworkEvent,
+            ScriptThreadEventCategory::PerformanceTimelineTask => {
+                ProfilerCategory::ScriptPerformanceEvent
+            },
+            ScriptThreadEventCategory::PortMessage => ProfilerCategory::ScriptPortMessage,
+            ScriptThreadEventCategory::Resize => ProfilerCategory::ScriptResize,
+            ScriptThreadEventCategory::ScriptEvent => ProfilerCategory::ScriptEvent,
+            ScriptThreadEventCategory::ServiceWorkerEvent => {
+                ProfilerCategory::ScriptServiceWorkerEvent
+            },
+            ScriptThreadEventCategory::SetScrollState => ProfilerCategory::ScriptSetScrollState,
+            ScriptThreadEventCategory::SetViewport => ProfilerCategory::ScriptSetViewport,
+            ScriptThreadEventCategory::StylesheetLoad => ProfilerCategory::ScriptStylesheetLoad,
+            ScriptThreadEventCategory::TimerEvent => ProfilerCategory::ScriptTimerEvent,
+            ScriptThreadEventCategory::UpdateReplacedElement => {
+                ProfilerCategory::ScriptUpdateReplacedElement
+            },
+            ScriptThreadEventCategory::WebSocketEvent => ProfilerCategory::ScriptWebSocketEvent,
+            ScriptThreadEventCategory::WorkerEvent => ProfilerCategory::ScriptWorkerEvent,
+            ScriptThreadEventCategory::WorkletEvent => ProfilerCategory::ScriptWorkletEvent,
+            #[cfg(feature = "webgpu")]
+            ScriptThreadEventCategory::WebGPUMsg => ProfilerCategory::ScriptWebGPUMsg,
+        }
+    }
+}
+
+impl From<ScriptThreadEventCategory> for ScriptHangAnnotation {
+    fn from(category: ScriptThreadEventCategory) -> Self {
+        match category {
+            ScriptThreadEventCategory::AttachLayout => ScriptHangAnnotation::AttachLayout,
+            ScriptThreadEventCategory::ConstellationMsg => ScriptHangAnnotation::ConstellationMsg,
+            ScriptThreadEventCategory::DevtoolsMsg => ScriptHangAnnotation::DevtoolsMsg,
+            ScriptThreadEventCategory::DocumentEvent => ScriptHangAnnotation::DocumentEvent,
+            ScriptThreadEventCategory::DomEvent => ScriptHangAnnotation::DomEvent,
+            ScriptThreadEventCategory::FileRead => ScriptHangAnnotation::FileRead,
+            ScriptThreadEventCategory::FormPlannedNavigation => {
+                ScriptHangAnnotation::FormPlannedNavigation
+            },
+            ScriptThreadEventCategory::HistoryEvent => ScriptHangAnnotation::HistoryEvent,
+            ScriptThreadEventCategory::ImageCacheMsg => ScriptHangAnnotation::ImageCacheMsg,
+            ScriptThreadEventCategory::InputEvent => ScriptHangAnnotation::InputEvent,
+            ScriptThreadEventCategory::NetworkEvent => ScriptHangAnnotation::NetworkEvent,
+            ScriptThreadEventCategory::Resize => ScriptHangAnnotation::Resize,
+            ScriptThreadEventCategory::ScriptEvent => ScriptHangAnnotation::ScriptEvent,
+            ScriptThreadEventCategory::SetScrollState => ScriptHangAnnotation::SetScrollState,
+            ScriptThreadEventCategory::SetViewport => ScriptHangAnnotation::SetViewport,
+            ScriptThreadEventCategory::StylesheetLoad => ScriptHangAnnotation::StylesheetLoad,
+            ScriptThreadEventCategory::TimerEvent => ScriptHangAnnotation::TimerEvent,
+            ScriptThreadEventCategory::UpdateReplacedElement => {
+                ScriptHangAnnotation::UpdateReplacedElement
+            },
+            ScriptThreadEventCategory::WebSocketEvent => ScriptHangAnnotation::WebSocketEvent,
+            ScriptThreadEventCategory::WorkerEvent => ScriptHangAnnotation::WorkerEvent,
+            ScriptThreadEventCategory::WorkletEvent => ScriptHangAnnotation::WorkletEvent,
+            ScriptThreadEventCategory::ServiceWorkerEvent => {
+                ScriptHangAnnotation::ServiceWorkerEvent
+            },
+            ScriptThreadEventCategory::EnterFullscreen => ScriptHangAnnotation::EnterFullscreen,
+            ScriptThreadEventCategory::ExitFullscreen => ScriptHangAnnotation::ExitFullscreen,
+            ScriptThreadEventCategory::PerformanceTimelineTask => {
+                ScriptHangAnnotation::PerformanceTimelineTask
+            },
+            ScriptThreadEventCategory::PortMessage => ScriptHangAnnotation::PortMessage,
+            #[cfg(feature = "webgpu")]
+            ScriptThreadEventCategory::WebGPUMsg => ScriptHangAnnotation::WebGPUMsg,
+        }
+    }
+}
+
 /// An interface for receiving ScriptMsg values in an event loop. Used for synchronous DOM
 /// APIs that need to abstract over multiple kinds of event loops (worker/main thread) with
 /// different Receiver interfaces.

components/script/task_manager.rs

@@ -6,7 +6,10 @@ use std::collections::HashMap;
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
 
+use base::id::PipelineId;
+
 use crate::dom::bindings::cell::DomRefCell;
+use crate::messaging::MainThreadScriptChan;
 use crate::task::TaskCanceller;
 use crate::task_source::dom_manipulation::DOMManipulationTaskSource;
 use crate::task_source::file_reading::FileReadingTaskSource;
@@ -24,15 +27,20 @@ use crate::task_source::websocket::WebsocketTaskSource;
 use crate::task_source::TaskSourceName;
 
 macro_rules! task_source_functions {
+    ($self:ident, $task_source:ident, $task_source_type:ident, $task_source_name:ident) => {
+        pub(crate) fn $task_source(&$self) -> $task_source_type {
+            $self.$task_source.clone()
+        }
+    };
     ($self:ident, $with_canceller:ident, $task_source:ident, $task_source_type:ident, $task_source_name:ident) => {
-        pub fn $with_canceller(&$self) -> ($task_source_type, TaskCanceller) {
+        pub(crate) fn $with_canceller(&$self) -> ($task_source_type, TaskCanceller) {
             ($self.$task_source.clone(), $self.task_canceller(TaskSourceName::$task_source_name))
         }
 
-        pub fn $task_source(&$self) -> $task_source_type {
+        pub(crate) fn $task_source(&$self) -> $task_source_type {
             $self.$task_source.clone()
         }
-    }
+    };
 }
 
 #[derive(JSTraceable, MallocSizeOf)]
@@ -69,35 +77,27 @@ pub struct TaskManager {
 
 impl TaskManager {
     #[allow(clippy::too_many_arguments)]
-    pub fn new(
+    pub(crate) fn new(sender: Box<MainThreadScriptChan>, pipeline_id: PipelineId) -> Self {
-        dom_manipulation_task_source: DOMManipulationTaskSource,
-        file_reading_task_source: FileReadingTaskSource,
-        gamepad_task_source: GamepadTaskSource,
-        history_traversal_task_source: HistoryTraversalTaskSource,
-        media_element_task_source: MediaElementTaskSource,
-        networking_task_source: NetworkingTaskSource,
-        performance_timeline_task_source: PerformanceTimelineTaskSource,
-        port_message_queue: PortMessageQueue,
-        user_interaction_task_source: UserInteractionTaskSource,
-        remote_event_task_source: RemoteEventTaskSource,
-        rendering_task_source: RenderingTaskSource,
-        timer_task_source: TimerTaskSource,
-        websocket_task_source: WebsocketTaskSource,
-    ) -> Self {
         TaskManager {
-            dom_manipulation_task_source,
+            dom_manipulation_task_source: DOMManipulationTaskSource(sender.clone(), pipeline_id),
-            file_reading_task_source,
+            file_reading_task_source: FileReadingTaskSource(sender.clone(), pipeline_id),
-            gamepad_task_source,
+            gamepad_task_source: GamepadTaskSource(sender.clone(), pipeline_id),
-            history_traversal_task_source,
+            history_traversal_task_source: HistoryTraversalTaskSource(
-            media_element_task_source,
+                sender.0.clone(),
-            networking_task_source,
+                pipeline_id,
-            performance_timeline_task_source,
+            ),
-            port_message_queue,
+            media_element_task_source: MediaElementTaskSource(sender.0.clone(), pipeline_id),
-            user_interaction_task_source,
+            networking_task_source: NetworkingTaskSource(sender.clone(), pipeline_id),
-            remote_event_task_source,
+            performance_timeline_task_source: PerformanceTimelineTaskSource(
-            rendering_task_source,
+                sender.clone(),
-            timer_task_source,
+                pipeline_id,
-            websocket_task_source,
+            ),
+            port_message_queue: PortMessageQueue(sender.clone(), pipeline_id),
+            user_interaction_task_source: UserInteractionTaskSource(sender.0.clone(), pipeline_id),
+            remote_event_task_source: RemoteEventTaskSource(sender.clone(), pipeline_id),
+            rendering_task_source: RenderingTaskSource(sender.clone(), pipeline_id),
+            timer_task_source: TimerTaskSource(sender.clone(), pipeline_id),
+            websocket_task_source: WebsocketTaskSource(sender.clone(), pipeline_id),
             task_cancellers: Default::default(),
         }
     }
@@ -110,13 +110,7 @@ impl TaskManager {
         DOMManipulation
     );
 
-    task_source_functions!(
+    task_source_functions!(self, gamepad_task_source, GamepadTaskSource, Gamepad);
-        self,
-        gamepad_task_source_with_canceller,
-        gamepad_task_source,
-        GamepadTaskSource,
-        Gamepad
-    );
 
     task_source_functions!(
         self,
@@ -128,7 +122,6 @@ impl TaskManager {
 
     task_source_functions!(
         self,
-        user_interaction_task_source_with_canceller,
         user_interaction_task_source,
         UserInteractionTaskSource,
         UserInteraction
@@ -144,7 +137,6 @@ impl TaskManager {
 
     task_source_functions!(
         self,
-        file_reading_task_source_with_canceller,
         file_reading_task_source,
         FileReadingTaskSource,
         FileReading
@@ -152,59 +144,25 @@ impl TaskManager {
 
     task_source_functions!(
         self,
-        history_traversal_task_source_with_canceller,
-        history_traversal_task_source,
-        HistoryTraversalTaskSource,
-        HistoryTraversal
-    );
-
-    task_source_functions!(
-        self,
-        performance_timeline_task_source_with_canceller,
         performance_timeline_task_source,
         PerformanceTimelineTaskSource,
         PerformanceTimeline
     );
 
-    task_source_functions!(
+    task_source_functions!(self, port_message_queue, PortMessageQueue, PortMessage);
-        self,
-        port_message_queue_with_canceller,
-        port_message_queue,
-        PortMessageQueue,
-        PortMessage
-    );
 
     task_source_functions!(
         self,
-        remote_event_task_source_with_canceller,
         remote_event_task_source,
         RemoteEventTaskSource,
         RemoteEvent
     );
 
-    task_source_functions!(
+    task_source_functions!(self, rendering_task_source, RenderingTaskSource, Rendering);
-        self,
-        rendering_task_source_with_canceller,
-        rendering_task_source,
-        RenderingTaskSource,
-        Rendering
-    );
 
-    task_source_functions!(
+    task_source_functions!(self, timer_task_source, TimerTaskSource, Timer);
-        self,
-        timer_task_source_with_canceller,
-        timer_task_source,
-        TimerTaskSource,
-        Timer
-    );
 
-    task_source_functions!(
+    task_source_functions!(self, websocket_task_source, WebsocketTaskSource, Websocket);
-        self,
-        websocket_task_source_with_canceller,
-        websocket_task_source,
-        WebsocketTaskSource,
-        Websocket
-    );
 
     pub fn task_canceller(&self, name: TaskSourceName) -> TaskCanceller {
         let mut flags = self.task_cancellers.borrow_mut();

components/script/task_source/dom_manipulation.rs

@@ -22,7 +22,7 @@ pub struct DOMManipulationTaskSource(pub Box<dyn ScriptChan + Send>, #[no_trace]
 
 impl Clone for DOMManipulationTaskSource {
     fn clone(&self) -> DOMManipulationTaskSource {
-        DOMManipulationTaskSource(self.0.clone(), self.1)
+        DOMManipulationTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/file_reading.rs

@@ -18,7 +18,7 @@ pub struct FileReadingTaskSource(
 
 impl Clone for FileReadingTaskSource {
     fn clone(&self) -> FileReadingTaskSource {
-        FileReadingTaskSource(self.0.clone(), self.1)
+        FileReadingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/gamepad.rs

@@ -19,7 +19,7 @@ pub struct GamepadTaskSource(
 
 impl Clone for GamepadTaskSource {
     fn clone(&self) -> GamepadTaskSource {
-        GamepadTaskSource(self.0.clone(), self.1)
+        GamepadTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/history_traversal.rs

@@ -5,13 +5,13 @@
 use base::id::PipelineId;
 use crossbeam_channel::Sender;
 
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 
 #[derive(Clone, JSTraceable)]
-pub struct HistoryTraversalTaskSource(
+pub(crate) struct HistoryTraversalTaskSource(
     #[no_trace] pub Sender<MainThreadScriptMsg>,
     #[no_trace] pub PipelineId,
 );

components/script/task_source/media_element.rs

@@ -14,13 +14,13 @@ use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::event::SimpleEventTask;
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::window::Window;
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 
 #[derive(Clone, JSTraceable)]
-pub struct MediaElementTaskSource(
+pub(crate) struct MediaElementTaskSource(
     #[no_trace] pub Sender<MainThreadScriptMsg>,
     #[no_trace] pub PipelineId,
 );

components/script/task_source/networking.rs

@@ -16,7 +16,7 @@ pub struct NetworkingTaskSource(
 
 impl Clone for NetworkingTaskSource {
     fn clone(&self) -> NetworkingTaskSource {
-        NetworkingTaskSource(self.0.clone(), self.1)
+        NetworkingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/performance_timeline.rs

@@ -25,7 +25,7 @@ pub struct PerformanceTimelineTaskSource(
 
 impl Clone for PerformanceTimelineTaskSource {
     fn clone(&self) -> PerformanceTimelineTaskSource {
-        PerformanceTimelineTaskSource(self.0.clone(), self.1)
+        PerformanceTimelineTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/port_message.rs

@@ -18,7 +18,7 @@ pub struct PortMessageQueue(
 
 impl Clone for PortMessageQueue {
     fn clone(&self) -> PortMessageQueue {
-        PortMessageQueue(self.0.clone(), self.1)
+        PortMessageQueue(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/remote_event.rs

@@ -16,7 +16,7 @@ pub struct RemoteEventTaskSource(
 
 impl Clone for RemoteEventTaskSource {
     fn clone(&self) -> RemoteEventTaskSource {
-        RemoteEventTaskSource(self.0.clone(), self.1)
+        RemoteEventTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/rendering.rs

@@ -16,7 +16,7 @@ pub struct RenderingTaskSource(pub Box<dyn ScriptChan + Send>, #[no_trace] pub P
 
 impl Clone for RenderingTaskSource {
     fn clone(&self) -> RenderingTaskSource {
-        RenderingTaskSource(self.0.clone(), self.1)
+        RenderingTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/timer.rs

@@ -19,7 +19,7 @@ pub struct TimerTaskSource(
 
 impl Clone for TimerTaskSource {
     fn clone(&self) -> TimerTaskSource {
-        TimerTaskSource(self.0.clone(), self.1)
+        TimerTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/script/task_source/user_interaction.rs

@@ -14,8 +14,8 @@ use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::event::{EventBubbles, EventCancelable, EventTask};
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::window::Window;
+use crate::messaging::MainThreadScriptMsg;
 use crate::script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
-use crate::script_thread::MainThreadScriptMsg;
 use crate::task::{TaskCanceller, TaskOnce};
 use crate::task_source::{TaskSource, TaskSourceName};
 

components/script/task_source/websocket.rs

@@ -16,7 +16,7 @@ pub struct WebsocketTaskSource(
 
 impl Clone for WebsocketTaskSource {
     fn clone(&self) -> WebsocketTaskSource {
-        WebsocketTaskSource(self.0.clone(), self.1)
+        WebsocketTaskSource(self.0.as_boxed(), self.1)
     }
 }
 

components/shared/script/lib.rs

@@ -616,33 +616,33 @@ pub struct InitialScriptState {
     /// Loading into a Secure Context
     pub inherited_secure_context: Option<bool>,
     /// A channel with which messages can be sent to us (the script thread).
-    pub control_chan: IpcSender<ConstellationControlMsg>,
+    pub constellation_sender: IpcSender<ConstellationControlMsg>,
     /// A port on which messages sent by the constellation to script can be received.
-    pub control_port: IpcReceiver<ConstellationControlMsg>,
+    pub constellation_receiver: IpcReceiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
-    pub script_to_constellation_chan: ScriptToConstellationChan,
+    pub pipeline_to_constellation_sender: ScriptToConstellationChan,
     /// A handle to register script-(and associated layout-)threads for hang monitoring.
     pub background_hang_monitor_register: Box<dyn BackgroundHangMonitorRegister>,
     /// A sender layout to communicate to the constellation.
-    pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
+    pub layout_to_constellation_ipc_sender: IpcSender<LayoutMsg>,
     /// A channel to the resource manager thread.
     pub resource_threads: ResourceThreads,
     /// A channel to the bluetooth thread.
-    pub bluetooth_thread: IpcSender<BluetoothRequest>,
+    pub bluetooth_sender: IpcSender<BluetoothRequest>,
     /// The image cache for this script thread.
     pub image_cache: Arc<dyn ImageCache>,
     /// A channel to the time profiler thread.
-    pub time_profiler_chan: profile_traits::time::ProfilerChan,
+    pub time_profiler_sender: profile_traits::time::ProfilerChan,
     /// A channel to the memory profiler thread.
-    pub mem_profiler_chan: mem::ProfilerChan,
+    pub memory_profiler_sender: mem::ProfilerChan,
     /// A channel to the developer tools, if applicable.
-    pub devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
+    pub devtools_server_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     /// Information about the initial window size.
     pub window_size: WindowSizeData,
     /// The ID of the pipeline namespace for this script thread.
     pub pipeline_namespace_id: PipelineNamespaceId,
     /// A ping will be sent on this channel once the script thread shuts down.
-    pub content_process_shutdown_chan: Sender<()>,
+    pub content_process_shutdown_sender: Sender<()>,
     /// A channel to the WebGL thread used in this pipeline.
     pub webgl_chan: Option<WebGLPipeline>,
     /// The XR device registry