Move `ScriptToConstellationMsg` to `constellation_traits` (#36364)

This is the last big change necessary to create the
`constellation_traits` crate. This moves the data structure for messages
that originate from the `ScriptThread` and are sent to the
`Contellation` to `constellation_traits`, effectively splitting
`script_traits` in half. Before, `script_traits` was responsible for
exposing the API of both the `ScriptThread` and the `Constellation` to
the rest of Servo.

- Data structures that are used by `ScriptToConstellationMsg` are moved
  to `constellation_traits`. The dependency graph looks a bit like this:
  `script_layout_interface` depends on `script_traits` depends on
  `constellation_traits` depends on `embedder_traits`.
- Data structures that are used in the embedding layer
  (`UntrustedNodeAddress`, `CompositorHitTestResult`, `TouchEventResult`
  and `AnimationState`) are moved to embedder_traits, to avoid a
  dependency cycle between `webrender_traits` and
  `constellation_traits`.
- Types dealing with MessagePorts and serialization are moved to
  `constellation_traits::message_port`.

Testing: This is covered by existing tests as it just moves types
around.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/components/shared/compositing/lib.rs b/components/shared/compositing/lib.rs
index 738619ffc31..9c13afb8dc3 100644
--- a/components/shared/compositing/lib.rs
+++ b/components/shared/compositing/lib.rs
@@ -8,12 +8,13 @@ use std::fmt::{Debug, Error, Formatter};
 
 use base::id::{PipelineId, WebViewId};
 use crossbeam_channel::{Receiver, Sender};
-use embedder_traits::{EventLoopWaker, MouseButton, MouseButtonAction};
+use embedder_traits::{
+    AnimationState, EventLoopWaker, MouseButton, MouseButtonAction, TouchEventResult,
+};
 use euclid::Rect;
 use ipc_channel::ipc::IpcSender;
 use log::warn;
 use pixels::Image;
-use script_traits::{AnimationState, TouchEventResult};
 use strum_macros::IntoStaticStr;
 use style_traits::CSSPixel;
 use webrender_api::DocumentId;