servo: Merge #11410 - Remove the script listener thread (from Ms2ger:script-listener-thread); r=nox

Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data:
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy --faster` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

Either:
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because refactoring

Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process.

Source-Repo: https://github.com/servo/servo
Source-Revision: 1640ade0b3f703b54c2c2285271d44a037f7eabc

servo/components/script/script_thread.rs

@@ -81,7 +81,7 @@ use script_traits::CompositorEvent::{TouchEvent, TouchpadPressureEvent};
 use script_traits::{CompositorEvent, ConstellationControlMsg, EventResult};
 use script_traits::{InitialScriptState, MouseButton, MouseEventType, MozBrowserEvent, NewLayoutInfo};
 use script_traits::{LayoutMsg, ScriptMsg as ConstellationMsg};
-use script_traits::{ScriptThreadFactory, ScriptToCompositorMsg, TimerEvent, TimerEventRequest, TimerSource};
+use script_traits::{ScriptThreadFactory, TimerEvent, TimerEventRequest, TimerSource};
 use script_traits::{TouchEventType, TouchId};
 use std::borrow::ToOwned;
 use std::cell::{Cell, RefCell};
@@ -350,9 +350,6 @@ pub struct ScriptThread {
     /// For communicating layout messages to the constellation
     layout_to_constellation_chan: IpcSender<LayoutMsg>,
 
-    /// A handle to the compositor for communicating ready state messages.
-    compositor: IpcSender<ScriptToCompositorMsg>,
-
     /// The port on which we receive messages from the image cache
     image_cache_port: Receiver<ImageCacheResult>,
 
@@ -465,7 +462,6 @@ impl ScriptThreadFactory for ScriptThread {
             let reporter_name = format!("script-reporter-{}", id);
             mem_profiler_chan.run_with_memory_reporting(|| {
                 script_thread.start();
-                let _ = script_thread.compositor.send(ScriptToCompositorMsg::Exited);
                 let _ = script_thread.content_process_shutdown_chan.send(());
             }, reporter_name, script_chan, CommonScriptMsg::CollectReports);
 
@@ -577,7 +573,6 @@ impl ScriptThread {
             control_port: control_port,
             constellation_chan: state.constellation_chan,
             layout_to_constellation_chan: state.layout_to_constellation_chan,
-            compositor: state.compositor,
             time_profiler_chan: state.time_profiler_chan,
             mem_profiler_chan: state.mem_profiler_chan,
             panic_chan: state.panic_chan,
@@ -1301,8 +1296,8 @@ impl ScriptThread {
 
         // TODO(tkuehn): currently there is only one window,
         // so this can afford to be naive and just shut down the
-        // compositor. In the future it'll need to be smarter.
-        self.compositor.send(ScriptToCompositorMsg::Exit).unwrap();
+        // constellation. In the future it'll need to be smarter.
+        self.constellation_chan.send(ConstellationMsg::Exit).unwrap();
     }
 
     /// We have received notification that the response associated with a load has completed.
@@ -1459,7 +1454,6 @@ impl ScriptThread {
                                  FileReadingTaskSource(file_sender.clone()),
                                  self.image_cache_channel.clone(),
                                  self.custom_message_chan.clone(),
-                                 self.compositor.clone(),
                                  self.image_cache_thread.clone(),
                                  self.resource_threads.clone(),
                                  self.bluetooth_thread.clone(),
@@ -1682,8 +1676,11 @@ impl ScriptThread {
         let point = Point2D::new(rect.origin.x.to_nearest_px() as f32,
                                  rect.origin.y.to_nearest_px() as f32);
 
-        self.compositor.send(ScriptToCompositorMsg::ScrollFragmentPoint(
-                                                 pipeline_id, LayerId::null(), point, false)).unwrap();
+        let message = ConstellationMsg::ScrollFragmentPoint(pipeline_id,
+                                                            LayerId::null(),
+                                                            point,
+                                                            false);
+        self.constellation_chan.send(message).unwrap();
     }
 
     /// Reflows non-incrementally, rebuilding the entire layout tree in the process.
@@ -1768,16 +1765,14 @@ impl ScriptThread {
                 let handled = self.handle_touch_event(pipeline_id, event_type, identifier, point);
                 match event_type {
                     TouchEventType::Down => {
-                        if handled {
+                        let result = if handled {
                             // TODO: Wait to see if preventDefault is called on the first touchmove event.
-                            self.compositor
-                                .send(ScriptToCompositorMsg::TouchEventProcessed(
-                                        EventResult::DefaultAllowed)).unwrap();
+                            EventResult::DefaultAllowed
                         } else {
-                            self.compositor
-                                .send(ScriptToCompositorMsg::TouchEventProcessed(
-                                        EventResult::DefaultPrevented)).unwrap();
-                        }
+                            EventResult::DefaultPrevented
+                        };
+                        let message = ConstellationMsg::TouchEventProcessed(result);
+                        self.constellation_chan.send(message).unwrap();
                     }
                     _ => {
                         // TODO: Calling preventDefault on a touchup event should prevent clicks.
@@ -1794,7 +1789,7 @@ impl ScriptThread {
             KeyEvent(key, state, modifiers) => {
                 let context = get_browsing_context(&self.root_browsing_context(), pipeline_id);
                 let document = context.active_document();
-                document.dispatch_key_event(key, state, modifiers, &self.compositor);
+                document.dispatch_key_event(key, state, modifiers, &self.constellation_chan);
             }
         }
     }