Auto merge of #26921 - mrobinson:animation-set-key, r=jdm

Add DocumentAnimationSet and AnimationSetKey

This will be used in order to hold animations for pseudo elements in the
DocumentAnimationSet. Also no longer store the OpaqueNode in the
animation and transition data structures. This is already part of the
DocumentAnimationSet key.

---
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components/script_layout_interface/message.rs

@@ -7,13 +7,11 @@ use crate::{PendingImage, TrustedNodeAddress};
 use app_units::Au;
 use crossbeam_channel::{Receiver, Sender};
 use euclid::default::{Point2D, Rect};
-use fxhash::FxHashMap;
 use gfx_traits::Epoch;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use metrics::PaintTimeMetrics;
 use msg::constellation_msg::{BackgroundHangMonitorRegister, BrowsingContextId, PipelineId};
 use net_traits::image_cache::ImageCache;
-use parking_lot::RwLock;
 use profile_traits::mem::ReportsChan;
 use script_traits::Painter;
 use script_traits::{
@@ -25,7 +23,7 @@ use servo_atoms::Atom;
 use servo_url::{ImmutableOrigin, ServoUrl};
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
-use style::animation::ElementAnimationSet;
+use style::animation::DocumentAnimationSet;
 use style::context::QuirksMode;
 use style::dom::OpaqueNode;
 use style::invalidation::element::restyle_hints::RestyleHint;
@@ -215,7 +213,7 @@ pub struct ScriptReflow {
     /// The current animation timeline value.
     pub animation_timeline_value: f64,
     /// The set of animations for this document.
-    pub animations: ServoArc<RwLock<FxHashMap<OpaqueNode, ElementAnimationSet>>>,
+    pub animations: DocumentAnimationSet,
 }
 
 pub struct LayoutThreadInit {