Port ScriptToConstellation channel to generic channel (#38990)

This change was previously part of
fb1c0a4c48, which got reverted due to an
issue
with the compositor channel.

Split this change out into a separate PR, as it probably should have
been in the first place. Presumably it was one change before, since
serialization of crossbeam generic channels in single-process mode was
not implemented yet at the time.

Testing: Covered by existing tests. No custom callbacks involved.

Part of #38912

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>

components/constellation/constellation.rs

@@ -290,7 +290,7 @@ pub struct Constellation<STF, SWF> {
 
     /// An IPC channel for script threads to send messages to the constellation.
     /// This is the script threads' view of `script_receiver`.
-    script_sender: IpcSender<(PipelineId, ScriptToConstellationMessage)>,
+    script_sender: GenericSender<(PipelineId, ScriptToConstellationMessage)>,
 
     /// A channel for the constellation to receive messages from script threads.
     /// This is the constellation's view of `script_sender`.
@@ -607,11 +607,8 @@ where
             .name("Constellation".to_owned())
             .spawn(move || {
                 let (script_ipc_sender, script_ipc_receiver) =
-                    ipc::channel().expect("ipc channel failure");
-                let script_receiver =
-                    route_ipc_receiver_to_new_crossbeam_receiver_preserving_errors(
-                        script_ipc_receiver,
-                    );
+                    generic_channel::channel().expect("ipc channel failure");
+                let script_receiver = script_ipc_receiver.route_preserving_errors();
 
                 let (namespace_ipc_sender, namespace_ipc_receiver) =
                     generic_channel::channel().expect("ipc channel failure");

components/script/dom/workletglobalscope.rs

@@ -4,6 +4,7 @@
 
 use std::sync::Arc;
 
+use base::generic_channel::GenericSender;
 use base::id::PipelineId;
 use constellation_traits::{ScriptToConstellationChan, ScriptToConstellationMessage};
 use crossbeam_channel::Sender;
@@ -196,7 +197,7 @@ pub(crate) struct WorkletGlobalScopeInit {
     /// Channel to devtools
     pub(crate) devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     /// Messages to send to constellation
-    pub(crate) to_constellation_sender: IpcSender<(PipelineId, ScriptToConstellationMessage)>,
+    pub(crate) to_constellation_sender: GenericSender<(PipelineId, ScriptToConstellationMessage)>,
     /// The image cache
     pub(crate) image_cache: Arc<dyn ImageCache>,
     /// Identity manager for WebGPU resources

components/script/messaging.rs

@@ -340,7 +340,7 @@ pub(crate) struct ScriptThreadSenders {
     /// particular pipelines.
     #[no_trace]
     pub(crate) pipeline_to_constellation_sender:
-        IpcSender<(PipelineId, ScriptToConstellationMessage)>,
+        GenericSender<(PipelineId, ScriptToConstellationMessage)>,
 
     /// The shared [`IpcSender`] which is sent to the `ImageCache` when requesting an image. The
     /// messages on this channel are routed to crossbeam [`Sender`] on the router thread, which

components/shared/constellation/from_script_message.rs

@@ -8,6 +8,7 @@ use std::collections::HashMap;
 use std::fmt;
 
 use base::Epoch;
+use base::generic_channel::{GenericSender, SendResult};
 use base::id::{
     BroadcastChannelRouterId, BrowsingContextId, HistoryStateId, MessagePortId,
     MessagePortRouterId, PipelineId, ServiceWorkerId, ServiceWorkerRegistrationId, WebViewId,
@@ -23,7 +24,6 @@ use embedder_traits::{
 use euclid::default::Size2D as UntypedSize2D;
 use fonts_traits::SystemFontServiceProxySender;
 use http::{HeaderMap, Method};
-use ipc_channel::Error as IpcError;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use malloc_size_of_derive::MallocSizeOf;
 use net_traits::policy_container::PolicyContainer;
@@ -48,14 +48,14 @@ use crate::{
 #[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
 pub struct ScriptToConstellationChan {
     /// Sender for communicating with constellation thread.
-    pub sender: IpcSender<(PipelineId, ScriptToConstellationMessage)>,
+    pub sender: GenericSender<(PipelineId, ScriptToConstellationMessage)>,
     /// Used to identify the origin of the message.
     pub pipeline_id: PipelineId,
 }
 
 impl ScriptToConstellationChan {
     /// Send ScriptMsg and attach the pipeline_id to the message.
-    pub fn send(&self, msg: ScriptToConstellationMessage) -> Result<(), IpcError> {
+    pub fn send(&self, msg: ScriptToConstellationMessage) -> SendResult {
         self.sender.send((self.pipeline_id, msg))
     }
 }