Start having animations conform to the HTML spec

This is a small step toward fixing #19242. The main idea is that the
clock for animations should advance as the event loop ticks. We
accomplish this by moving the clock from layout and naming it the
"animation timeline" which is the spec language. This should fix
flakiness with animations and transitions tests where a reflow could
move animations forward while script was running.

This change also starts to break out transition and animation events
into their own data structure, because it's quite likely that the next
step in fixing #19242 is to no longer send these events through a
channel.

1 files changed, 10 insertions, 8 deletions

diff --git a/components/layout/animation.rs b/components/layout/animation.rs
index 09e3c75ec2c..c85d962008c 100644
--- a/components/layout/animation.rs
+++ b/components/layout/animation.rs
@@ -13,7 +13,7 @@ use msg::constellation_msg::PipelineId;
 use script_traits::UntrustedNodeAddress;
 use script_traits::{
     AnimationState, ConstellationControlMsg, LayoutMsg as ConstellationMsg,
-    TransitionOrAnimationEventType,
+    TransitionOrAnimationEvent, TransitionOrAnimationEventType,
 };
 use style::animation::{Animation, ElementAnimationState};
 
@@ -120,13 +120,15 @@ fn update_animation_state(
         };
 
         script_channel
-            .send(ConstellationControlMsg::TransitionOrAnimationEvent {
-                pipeline_id,
-                event_type,
-                node: node.to_untrusted_node_address(),
-                property_or_animation_name,
-                elapsed_time,
-            })
+            .send(ConstellationControlMsg::TransitionOrAnimationEvent(
+                TransitionOrAnimationEvent {
+                    pipeline_id,
+                    event_type,
+                    node: node.to_untrusted_node_address(),
+                    property_or_animation_name,
+                    elapsed_time,
+                },
+            ))
             .unwrap()
     };