Introduce GlobalScope::get_runnable_wrapper

components/script/dom/bindings/global.rs

@@ -19,7 +19,7 @@ use js::glue::{IsWrapper, UnwrapObject};
 use js::jsapi::{CurrentGlobalOrNull, GetGlobalForObjectCrossCompartment};
 use js::jsapi::{JSContext, JSObject, JS_GetClass};
 use script_runtime::{CommonScriptMsg, EnqueuedPromiseCallback, ScriptChan, ScriptPort};
-use script_thread::{RunnableWrapper, ScriptThread};
+use script_thread::ScriptThread;
 use task_source::file_reading::FileReadingTaskSource;
 
 /// A freely-copyable reference to a rooted global object.
@@ -85,15 +85,6 @@ impl<'a> GlobalRef<'a> {
         }
     }
 
-    /// Returns a wrapper for runnables to ensure they are cancelled if the global
-    /// is being destroyed.
-    pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
-        match *self {
-            GlobalRef::Window(ref window) => window.get_runnable_wrapper(),
-            GlobalRef::Worker(ref worker) => worker.get_runnable_wrapper(),
-        }
-    }
-
     /// Enqueue a promise callback for subsequent execution.
     pub fn enqueue_promise_job(&self, job: EnqueuedPromiseCallback) {
         match *self {

components/script/dom/filereader.rs

@@ -354,7 +354,7 @@ impl FileReader {
         let fr = Trusted::new(self);
         let gen_id = self.generation_id.get();
 
-        let wrapper = self.global().r().get_runnable_wrapper();
+        let wrapper = self.global_scope().get_runnable_wrapper();
         let task_source = self.global().r().file_reading_task_source();
 
         spawn_named("file reader async operation".to_owned(), move || {

components/script/dom/globalscope.rs

@@ -27,7 +27,7 @@ use msg::constellation_msg::PipelineId;
 use net_traits::{CoreResourceThread, ResourceThreads, IpcSend};
 use profile_traits::{mem, time};
 use script_runtime::{ScriptChan, maybe_take_panic_result};
-use script_thread::MainThreadScriptChan;
+use script_thread::{MainThreadScriptChan, RunnableWrapper};
 use script_traits::{MsDuration, ScriptMsg as ConstellationMsg, TimerEvent};
 use script_traits::{TimerEventId, TimerEventRequest, TimerSource};
 use std::cell::Cell;
@@ -396,6 +396,18 @@ impl GlobalScope {
         }
         unreachable!();
     }
+
+    /// Returns a wrapper for runnables to ensure they are cancelled if
+    /// the global scope is being destroyed.
+    pub fn get_runnable_wrapper(&self) -> RunnableWrapper {
+        if let Some(window) = self.downcast::<Window>() {
+            return window.get_runnable_wrapper();
+        }
+        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
+            return worker.get_runnable_wrapper();
+        }
+        unreachable!();
+    }
 }
 
 fn timestamp_in_ms(time: Timespec) -> u64 {

components/script/task_source/mod.rs

@@ -19,6 +19,6 @@ pub trait TaskSource {
                              -> Result<(), ()>
                              where T: Runnable + Send + 'static;
     fn queue<T: Runnable + Send + 'static>(&self, msg: Box<T>, global: GlobalRef) -> Result<(), ()> {
-        self.queue_with_wrapper(msg, &global.get_runnable_wrapper())
+        self.queue_with_wrapper(msg, &global.as_global_scope().get_runnable_wrapper())
     }
 }