Implement TaskSource for HistoryTraversal

And remove the method in window that returns it, because it isn't used
so far.

components/profile/time.rs

@@ -129,6 +129,7 @@ impl Formattable for ProfilerCategory {
             ProfilerCategory::ScriptDomEvent => "Script Dom Event",
             ProfilerCategory::ScriptEvaluate => "Script JS Evaluate",
             ProfilerCategory::ScriptFileRead => "Script File Read",
+            ProfilerCategory::ScriptHistoryEvent => "Script History Event",
             ProfilerCategory::ScriptImageCacheMsg => "Script Image Cache Msg",
             ProfilerCategory::ScriptInputEvent => "Script Input Event",
             ProfilerCategory::ScriptNetworkEvent => "Script Network Event",

components/profile_traits/time.rs

@@ -103,6 +103,7 @@ pub enum ProfilerCategory {
     ScriptWebVREvent = 0x79,
     ScriptWorkletEvent = 0x7a,
     ScriptPerformanceEvent = 0x7b,
+    ScriptHistoryEvent = 0x7c,
     TimeToFirstPaint = 0x80,
     TimeToFirstContentfulPaint = 0x81,
     TimeToInteractive = 0x82,

components/script/dom/window.rs

@@ -381,12 +381,9 @@ impl Window {
         self.networking_task_source.clone()
     }
 
-    pub fn history_traversal_task_source(&self) -> Box<dyn ScriptChan + Send> {
-        self.history_traversal_task_source.clone()
-    }
-
-    pub fn file_reading_task_source(&self) -> FileReadingTaskSource {
-        self.file_reading_task_source.clone()
+    pub fn file_reading_task_source(&self) -> TaskManagement<FileReadingTaskSource> {
+        let canceller = self.task_canceller(TaskSourceName::FileReading);
+        TaskManagement(self.file_reading_task_source.clone(), canceller)
     }
 
     pub fn performance_timeline_task_source(&self) -> PerformanceTimelineTaskSource {

components/script/script_runtime.rs

@@ -100,6 +100,7 @@ pub enum ScriptThreadEventCategory {
     DomEvent,
     FileRead,
     FormPlannedNavigation,
+    HistoryEvent,
     ImageCacheMsg,
     InputEvent,
     NetworkEvent,

components/script/script_thread.rs

@@ -521,7 +521,7 @@ pub struct ScriptThread {
 
     networking_task_sender: Box<dyn ScriptChan>,
 
-    history_traversal_task_source: HistoryTraversalTaskSource,
+    history_traversal_task_sender: Sender<MainThreadScriptMsg>,
 
     file_reading_task_sender: Box<dyn ScriptChan>,
 
@@ -1042,7 +1042,7 @@ impl ScriptThread {
             performance_timeline_task_sender: boxed_script_sender.clone(),
             remote_event_task_sender: boxed_script_sender.clone(),
 
-            history_traversal_task_source: HistoryTraversalTaskSource(chan),
+            history_traversal_task_sender: chan.clone(),
 
             control_chan: state.control_chan,
             control_port: control_port,
@@ -1409,6 +1409,7 @@ impl ScriptThread {
                 ScriptThreadEventCategory::FormPlannedNavigation => {
                     ProfilerCategory::ScriptPlannedNavigation
                 },
+                ScriptThreadEventCategory::HistoryEvent => ProfilerCategory::ScriptHistoryEvent,
                 ScriptThreadEventCategory::ImageCacheMsg => ProfilerCategory::ScriptImageCacheMsg,
                 ScriptThreadEventCategory::InputEvent => ProfilerCategory::ScriptInputEvent,
                 ScriptThreadEventCategory::NetworkEvent => ProfilerCategory::ScriptNetworkEvent,
@@ -2180,6 +2181,13 @@ impl ScriptThread {
         PerformanceTimelineTaskSource(self.performance_timeline_task_sender.clone(), pipeline_id)
     }
 
+    pub fn history_traversal_task_source(
+        &self,
+        pipeline_id: PipelineId,
+    ) -> HistoryTraversalTaskSource {
+        HistoryTraversalTaskSource(self.history_traversal_task_sender.clone(), pipeline_id)
+    }
+
     pub fn user_interaction_task_source(
         &self,
         pipeline_id: PipelineId,
@@ -2560,7 +2568,6 @@ impl ScriptThread {
         );
 
         let MainThreadScriptChan(ref sender) = self.chan;
-        let HistoryTraversalTaskSource(ref history_sender) = self.history_traversal_task_source;
 
         let (ipc_timer_event_chan, ipc_timer_event_port) = ipc::channel().unwrap();
         route_ipc_receiver_to_new_servo_sender(ipc_timer_event_port, self.timer_event_chan.clone());
@@ -2584,7 +2591,7 @@ impl ScriptThread {
             self.media_element_task_source(incomplete.pipeline_id),
             self.user_interaction_task_source(incomplete.pipeline_id),
             self.networking_task_source(incomplete.pipeline_id),
-            HistoryTraversalTaskSource(history_sender.clone()),
+            self.history_traversal_task_source(incomplete.pipeline_id),
             self.file_reading_task_source(incomplete.pipeline_id),
             self.performance_timeline_task_source(incomplete.pipeline_id)
                 .clone(),

components/script/task_source/history_traversal.rs

@@ -2,12 +2,15 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use crate::script_runtime::{CommonScriptMsg, ScriptChan};
-use crate::script_thread::MainThreadScriptMsg;
+use msg::constellation_msg::PipelineId;
+use script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
+use script_thread::MainThreadScriptMsg;
 use servo_channel::Sender;
+use task::{TaskCanceller, TaskOnce};
+use task_source::{TaskSource, TaskSourceName};
 
 #[derive(JSTraceable)]
-pub struct HistoryTraversalTaskSource(pub Sender<MainThreadScriptMsg>);
+pub struct HistoryTraversalTaskSource(pub Sender<MainThreadScriptMsg>, pub PipelineId);
 
 impl ScriptChan for HistoryTraversalTaskSource {
     fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
@@ -16,7 +19,24 @@ impl ScriptChan for HistoryTraversalTaskSource {
             .map_err(|_| ())
     }
 
-    fn clone(&self) -> Box<dyn ScriptChan + Send> {
-        Box::new(HistoryTraversalTaskSource((&self.0).clone()))
+    fn clone(&self) -> Box<ScriptChan + Send> {
+        Box::new(HistoryTraversalTaskSource((&self.0).clone(), (&self.1).clone()))
+    }
+}
+
+impl TaskSource for HistoryTraversalTaskSource {
+    const NAME: TaskSourceName = TaskSourceName::HistoryTraversal;
+
+    fn queue_with_canceller<T>(&self, task: T, canceller: &TaskCanceller) -> Result<(), ()>
+    where
+        T: TaskOnce + 'static,
+    {
+        let msg = MainThreadScriptMsg::Common(CommonScriptMsg::Task(
+            ScriptThreadEventCategory::HistoryEvent,
+            Box::new(canceller.wrap_task(task)),
+            Some(self.1),
+            HistoryTraversalTaskSource::NAME,
+        ));
+        self.0.send(msg).map_err(|_| ())
     }
 }