script: generalize worker common code for non-dedicated worker globals (#44244)

Testing: No new tests needed this is a refactor and no behavior changes
for any existing workers.
part of https://github.com/servo/servo/issues/7458

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

components/script/dom/workers/dedicatedworkerglobalscope.rs

@@ -530,6 +530,7 @@ impl DedicatedWorkerGlobalScope {
                                 worker_url.url(),
                                 fetch_client,
                                 ModuleOwner::Worker(Trusted::new(scope)),
+                                Destination::Worker,
                                 referrer,
                                 credentials,
                             );

components/script/dom/workers/workerglobalscope.rs

@@ -571,10 +571,6 @@ impl WorkerGlobalScope {
     /// onComplete algorithm defined inside <https://html.spec.whatwg.org/multipage/#run-a-worker>
     #[expect(unsafe_code)]
     pub(crate) fn on_complete(&self, cx: &mut js::context::JSContext, script: Option<Script>) {
-        let dedicated_worker_scope = self
-            .downcast::<DedicatedWorkerGlobalScope>()
-            .expect("Only DedicatedWorkerGlobalScope is supported for now");
-
         // Step 1. If script is null or if script's error to rethrow is non-null, then:
         let script = match script {
             Some(Script::Classic(script)) if script.record.is_ok() => Script::Classic(script),
@@ -586,7 +582,9 @@ impl WorkerGlobalScope {
             _ => {
                 // Step 1.1 Queue a global task on the DOM manipulation task source given
                 // worker's relevant global object to fire an event named error at worker.
-                dedicated_worker_scope.forward_simple_error_at_worker();
+                if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
+                    dedicated.forward_simple_error_at_worker();
+                }
 
                 // TODO Step 1.2. Run the environment discarding steps for inside settings.
                 // Step 1.3 Abort these steps.
@@ -606,7 +604,7 @@ impl WorkerGlobalScope {
         {
             let mut realm = enter_auto_realm(cx, self);
             let cx = &mut realm.current_realm();
-            define_all_exposed_interfaces(cx, dedicated_worker_scope.upcast());
+            define_all_exposed_interfaces(cx, self.upcast());
             self.execution_ready.store(true, Ordering::Relaxed);
             match script {
                 Script::Classic(script) => {
@@ -619,7 +617,9 @@ impl WorkerGlobalScope {
                 },
                 _ => unreachable!(),
             }
-            dedicated_worker_scope.fire_queued_messages(CanGc::from_cx(cx));
+            if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
+                dedicated.fire_queued_messages(CanGc::from_cx(cx));
+            }
         }
     }
 

components/script/script_module.rs

@@ -1224,6 +1224,7 @@ pub(crate) fn fetch_a_module_worker_script_graph(
     url: ServoUrl,
     fetch_client: ModuleFetchClient,
     owner: ModuleOwner,
+    destination: Destination,
     referrer: Referrer,
     credentials_mode: CredentialsMode,
 ) {
@@ -1247,7 +1248,7 @@ pub(crate) fn fetch_a_module_worker_script_graph(
         url,
         fetch_client.clone(),
         owner.clone(),
-        Destination::Worker,
+        destination,
         options,
         referrer,
         None,
@@ -1265,7 +1266,7 @@ pub(crate) fn fetch_a_module_worker_script_graph(
                 cx,
                 module,
                 fetch_client,
-                Destination::Worker,
+                destination,
                 owner,
             );
         },