diff --git a/components/script/dom/serviceworkercontainer.rs b/components/script/dom/serviceworkercontainer.rs
index ba2e327409f..37e89714fe2 100644
--- a/components/script/dom/serviceworkercontainer.rs
+++ b/components/script/dom/serviceworkercontainer.rs
@@ -114,7 +114,7 @@ impl ServiceWorkerContainerMethods for ServiceWorkerContainer {
 
         // B: Step 8
         let job = Job::create_job(JobType::Register, scope, script_url, promise.clone(), &*self.client);
-        ScriptThread::schedule_job(job, &*self.global());
+        ScriptThread::schedule_job(job);
         promise
     }
 }
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index 2f7698ff960..21989316864 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -244,12 +244,6 @@ impl<T> Task for CancellableTask<T>
 where
     T: Send + Task,
 {
-    fn run_with_script_thread(self: Box<CancellableTask<T>>, script_thread: &ScriptThread) {
-        if !self.is_cancelled() {
-            self.inner.run_with_script_thread(script_thread);
-        }
-    }
-
     fn run(self: Box<Self>) {
         if !self.is_cancelled() {
             self.inner.run()
@@ -259,12 +253,7 @@ where
 
 pub trait Task {
     fn name(&self) -> &'static str { unsafe { intrinsics::type_name::<Self>() } }
-    fn run(self: Box<Self>) {
-        panic!("This should probably be redefined.")
-    }
-    fn run_with_script_thread(self: Box<Self>, _script_thread: &ScriptThread) {
-        self.run();
-    }
+    fn run(self: Box<Self>);
 }
 
 impl fmt::Debug for Task + Send {
@@ -304,8 +293,8 @@ pub enum MainThreadScriptMsg {
         properties: Vec<Atom>,
         painter: Box<Painter>
     },
-    /// Runs a Task in the main thread.
-    MainThreadTask(ScriptThreadEventCategory, Box<Task + Send>),
+    /// Dispatches a job queue.
+    DispatchJobQueue { scope_url: ServoUrl },
 }
 
 impl OpaqueSender<CommonScriptMsg> for Box<ScriptChan + Send> {
@@ -718,11 +707,11 @@ impl ScriptThread {
     }
 
     #[allow(unrooted_must_root)]
-    pub fn schedule_job(job: Job, global: &GlobalScope) {
+    pub fn schedule_job(job: Job) {
         SCRIPT_THREAD_ROOT.with(|root| {
             let script_thread = unsafe { &*root.get().unwrap() };
             let job_queue = &*script_thread.job_queue_map;
-            job_queue.schedule_job(job, global, &script_thread);
+            job_queue.schedule_job(job, &script_thread);
         });
     }
 
@@ -1192,8 +1181,9 @@ impl ScriptThread {
             MixedMessage::FromImageCache(_) => ScriptThreadEventCategory::ImageCacheMsg,
             MixedMessage::FromScript(ref inner_msg) => {
                 match *inner_msg {
-                    MainThreadScriptMsg::Common(CommonScriptMsg::Task(category, _)) |
-                    MainThreadScriptMsg::MainThreadTask(category, _) => category,
+                    MainThreadScriptMsg::Common(CommonScriptMsg::Task(category, _)) => {
+                        category
+                    },
                     MainThreadScriptMsg::RegisterPaintWorklet { .. } => {
                         ScriptThreadEventCategory::WorkletEvent
                     },
@@ -1348,9 +1338,9 @@ impl ScriptThread {
                     painter,
                 )
             },
-            MainThreadScriptMsg::MainThreadTask(_, task) => {
-                task.run_with_script_thread(self)
-            },
+            MainThreadScriptMsg::DispatchJobQueue { scope_url } => {
+                self.job_queue_map.run_job(scope_url, self)
+            }
         }
     }
 
@@ -1787,8 +1777,8 @@ impl ScriptThread {
         let _ = self.script_sender.send((pipeline_id, ScriptMsg::RegisterServiceWorker(scope_things, scope.clone())));
     }
 
-    pub fn dispatch_job_queue(&self, scope_url: ServoUrl) {
-        self.job_queue_map.run_job(scope_url, self);
+    pub fn schedule_job_queue(&self, scope_url: ServoUrl) {
+        let _ = self.chan.0.send(MainThreadScriptMsg::DispatchJobQueue { scope_url });
     }
 
     pub fn dom_manipulation_task_source(&self) -> &DOMManipulationTaskSource {
diff --git a/components/script/serviceworkerjob.rs b/components/script/serviceworkerjob.rs
index 41f875ab866..db457dc394a 100644
--- a/components/script/serviceworkerjob.rs
+++ b/components/script/serviceworkerjob.rs
@@ -93,25 +93,6 @@ impl PartialEq for Job {
     }
 }
 
-pub struct AsyncJobHandler {
-    pub scope_url: ServoUrl,
-}
-
-impl AsyncJobHandler {
-    fn new(scope_url: ServoUrl) -> AsyncJobHandler {
-        AsyncJobHandler {
-            scope_url: scope_url,
-        }
-    }
-}
-
-impl Task for AsyncJobHandler {
-    #[allow(unrooted_must_root)]
-    fn run_with_script_thread(self: Box<AsyncJobHandler>, script_thread: &ScriptThread) {
-        script_thread.dispatch_job_queue(self.scope_url);
-    }
-}
-
 #[must_root]
 #[derive(JSTraceable)]
 pub struct JobQueue(pub DOMRefCell<HashMap<ServoUrl, Vec<Job>>>);
@@ -122,10 +103,7 @@ impl JobQueue {
     }
     #[allow(unrooted_must_root)]
     // https://w3c.github.io/ServiceWorker/#schedule-job-algorithm
-    pub fn schedule_job(&self,
-                        job: Job,
-                        global: &GlobalScope,
-                        script_thread: &ScriptThread) {
+    pub fn schedule_job(&self, job: Job, script_thread: &ScriptThread) {
         debug!("scheduling {:?} job", job.job_type);
         let mut queue_ref = self.0.borrow_mut();
         let job_queue = queue_ref.entry(job.scope_url.clone()).or_insert(vec![]);
@@ -133,10 +111,7 @@ impl JobQueue {
         if job_queue.is_empty() {
             let scope_url = job.scope_url.clone();
             job_queue.push(job);
-            let _ = script_thread.dom_manipulation_task_source().queue_main_thread_task(
-                box AsyncJobHandler::new(scope_url),
-                global,
-            );
+            let _ = script_thread.schedule_job_queue(scope_url);
             debug!("queued task to run newly-queued job");
         } else {
             // Step 2
diff --git a/components/script/task_source/dom_manipulation.rs b/components/script/task_source/dom_manipulation.rs
index 0120564806c..f7b7a6577f8 100644
--- a/components/script/task_source/dom_manipulation.rs
+++ b/components/script/task_source/dom_manipulation.rs
@@ -6,7 +6,6 @@ use dom::bindings::inheritance::Castable;
 use dom::bindings::refcounted::Trusted;
 use dom::event::{EventBubbles, EventCancelable, EventTask, SimpleEventTask};
 use dom::eventtarget::EventTarget;
-use dom::globalscope::GlobalScope;
 use dom::window::Window;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::{MainThreadScriptMsg, Task, TaskCanceller};
@@ -43,21 +42,6 @@ impl TaskSource for DOMManipulationTaskSource {
 }
 
 impl DOMManipulationTaskSource {
-    pub fn queue_main_thread_task<T>(
-        &self,
-        task: Box<T>,
-        global: &GlobalScope,
-    ) -> Result<(), ()>
-    where
-        T: Task + Send + 'static,
-    {
-        let msg = MainThreadScriptMsg::MainThreadTask(
-            ScriptThreadEventCategory::ScriptEvent,
-            global.task_canceller().wrap_task(task),
-        );
-        self.0.send(msg).map_err(|_| ())
-    }
-
     pub fn queue_event(&self,
                        target: &EventTarget,
                        name: Atom,