Auto merge of #21325 - gterzian:crossbeam_integration, r=SimonSapin,jdm

Replace mpsc with crossbeam-channel

Follow up on https://github.com/servo/servo/pull/19515

---

Selecting over multiple channels in `std::sync::mpsc` is not stable and likely never will be:

https://github.com/rust-lang/rust/issues/27800#issuecomment-260136777
> It seems the only thing keeping `mpsc_select` around is Servo.

crossbeam-channel is designed specifically to replace `std::sync::mpsc` and fix many of its shortcomings:
https://github.com/stjepang/rfcs-crossbeam/blob/channel/text/2017-11-09-channel.md

This is to be landed together with https://github.com/servo/ipc-channel/pull/183.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/21325)
<!-- Reviewable:end -->

3 files changed, 3 insertions, 3 deletions

diff --git a/components/script/task_source/dom_manipulation.rs b/components/script/task_source/dom_manipulation.rs
index f184aa3d828..e72110479de 100644
--- a/components/script/task_source/dom_manipulation.rs
+++ b/components/script/task_source/dom_manipulation.rs
@@ -11,9 +11,9 @@ use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
+use servo_channel::Sender;
 use std::fmt;
 use std::result::Result;
-use std::sync::mpsc::Sender;
 use task::{TaskCanceller, TaskOnce};
 use task_source::{TaskSource, TaskSourceName};
 
diff --git a/components/script/task_source/history_traversal.rs b/components/script/task_source/history_traversal.rs
index ffd657adada..7f44ba368b5 100644
--- a/components/script/task_source/history_traversal.rs
+++ b/components/script/task_source/history_traversal.rs
@@ -4,7 +4,7 @@
 
 use script_runtime::{ScriptChan, CommonScriptMsg};
 use script_thread::MainThreadScriptMsg;
-use std::sync::mpsc::Sender;
+use servo_channel::Sender;
 
 #[derive(JSTraceable)]
 pub struct HistoryTraversalTaskSource(pub Sender<MainThreadScriptMsg>);
diff --git a/components/script/task_source/user_interaction.rs b/components/script/task_source/user_interaction.rs
index 2beaee95731..d30d54829b5 100644
--- a/components/script/task_source/user_interaction.rs
+++ b/components/script/task_source/user_interaction.rs
@@ -11,9 +11,9 @@ use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
+use servo_channel::Sender;
 use std::fmt;
 use std::result::Result;
-use std::sync::mpsc::Sender;
 use task::{TaskCanceller, TaskOnce};
 use task_source::{TaskSource, TaskSourceName};