Auto merge of #11375 - servo:layout_to_constellation_chan, r=mbrubeck

Remove ScriptThread::layout_to_constellation_chan.

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.

Instead, pass it along in NewLayoutInfo when needed.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/11375)
<!-- Reviewable:end -->

components/constellation/pipeline.rs

@@ -166,6 +166,7 @@ impl Pipeline {
                     paint_chan: layout_to_paint_chan.clone().to_opaque(),
                     panic_chan: state.panic_chan.clone(),
                     pipeline_port: pipeline_port,
+                    layout_to_constellation_chan: state.layout_to_constellation_chan.clone(),
                     layout_shutdown_chan: layout_shutdown_chan.clone(),
                     content_process_shutdown_chan: layout_content_process_shutdown_chan.clone(),
                 };
@@ -410,7 +411,6 @@ impl UnprivilegedPipelineContent {
             control_chan: self.script_chan.clone(),
             control_port: mem::replace(&mut self.script_port, None).expect("No script port."),
             constellation_chan: self.constellation_chan.clone(),
-            layout_to_constellation_chan: self.layout_to_constellation_chan.clone(),
             scheduler_chan: self.scheduler_chan.clone(),
             panic_chan: self.panic_chan.clone(),
             bluetooth_thread: self.bluetooth_thread.clone(),

components/script/script_thread.rs

@@ -79,8 +79,8 @@ use script_runtime::{ScriptPort, StackRootTLS, new_rt_and_cx, get_reports};
 use script_traits::CompositorEvent::{KeyEvent, MouseButtonEvent, MouseMoveEvent, ResizeEvent};
 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::{InitialScriptState, MouseButton, MouseEventType, MozBrowserEvent};
+use script_traits::{NewLayoutInfo, ScriptMsg as ConstellationMsg};
 use script_traits::{ScriptThreadFactory, TimerEvent, TimerEventRequest, TimerSource};
 use script_traits::{TouchEventType, TouchId};
 use std::borrow::ToOwned;
@@ -347,9 +347,6 @@ pub struct ScriptThread {
     /// For communicating load url messages to the constellation
     constellation_chan: IpcSender<ConstellationMsg>,
 
-    /// For communicating layout messages to the constellation
-    layout_to_constellation_chan: IpcSender<LayoutMsg>,
-
     /// The port on which we receive messages from the image cache
     image_cache_port: Receiver<ImageCacheResult>,
 
@@ -572,7 +569,6 @@ impl ScriptThread {
             control_chan: state.control_chan,
             control_port: control_port,
             constellation_chan: state.constellation_chan,
-            layout_to_constellation_chan: state.layout_to_constellation_chan,
             time_profiler_chan: state.time_profiler_chan,
             mem_profiler_chan: state.mem_profiler_chan,
             panic_chan: state.panic_chan,
@@ -1089,6 +1085,7 @@ impl ScriptThread {
             paint_chan,
             panic_chan,
             pipeline_port,
+            layout_to_constellation_chan,
             layout_shutdown_chan,
             content_process_shutdown_chan,
         } = new_layout_info;
@@ -1102,7 +1099,7 @@ impl ScriptThread {
             is_parent: false,
             layout_pair: layout_pair,
             pipeline_port: pipeline_port,
-            constellation_chan: self.layout_to_constellation_chan.clone(),
+            constellation_chan: layout_to_constellation_chan,
             panic_chan: panic_chan,
             paint_chan: paint_chan,
             script_chan: self.control_chan.clone(),

components/script_traits/lib.rs

@@ -100,6 +100,8 @@ pub struct NewLayoutInfo {
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     /// A channel for sending panics on
     pub panic_chan: IpcSender<PanicMsg>,
+    /// A sender for the layout thread to communicate to the constellation.
+    pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
     /// A shutdown channel so that layout can notify others when it's done.
     pub layout_shutdown_chan: IpcSender<()>,
     /// A shutdown channel so that layout can tell the content process to shut down when it's done.
@@ -310,8 +312,6 @@ pub struct InitialScriptState {
     pub control_port: IpcReceiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
     pub constellation_chan: IpcSender<ScriptMsg>,
-    /// A channel for the layout thread to send messages to the constellation.
-    pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
     /// A channel for sending panics to the constellation.
     pub panic_chan: IpcSender<PanicMsg>,
     /// A channel to schedule timer events.