commit 264c27d18a4d9736b14d6f9699b2d5507c19070f
author David Awogbemila <awogbemila@chromium.org> Wed Jun 04 13:18:50 2025
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jun 04 13:18:50 2025
tree da56c50308cd82d16b670cf9676533463d7fcd0b
parent e92a84bc051417c5dd51c78fbb7e37decd777087

[animation-trigger] Implement basic AnimationTrigger functionality

The discussion about how AnimationTrigger should work is ongoing. This
comment[1] captures the main points about how triggers should work.

The hope is to have a simple implementation which we can help guide what
the edge cases are, which ones we care about, and what to do about the
ones we care about.

A few points about the behavior worth highlighting are:

1. We automatically call addAnimation for CSS animations.

2. When animation-play-state is "paused" and isn't being ignored, the
   trigger should not play the animation.

3. Trigger-related state tracking is done only in the
   AnimationTrigger. However, we keep
   Animation::AnimationTriggerData::css_play_state just so the trigger
   can know not to play animations for which `animation-play-state`
   is paused.

A few notes about some other changes made in this patch.

1. inspector-protocol/tracing/animation-expected.txt is adjusted to
   expect "paused" instead of running because when we call
   addAnimation on the CSS animation, we'll pause it and Pause will
   be the first function to supply data to the
   inspector_animation_agent via NotifyProbe.

2. ElementAnimations::SetCompositedClipPathStatus is modified in a way
   that reflects the intention that kNotComposited and kNoAnimation
   clear clip_path_paint_worklet_candidate_, even if either of those
   was already recorded as the composited_clip_path_status_. The test
   case in clip_path_paint_definition_test.cc revealed (by
   unconditionally calling pause when the trigger is enabled) that
   ElementAnimations::RecalcCompositedStatus might set
   clip_path_paint_worklet_candidate_ and try to set the status to
   kNotComposited and kNoAnimation, but, because there is no change in
   the status, fail to clear clip_path_paint_worklet_candidate_.

[1]
https://github.com/w3c/csswg-drafts/issues/12119#issuecomment-2911260299

Bug: 390314945
Change-Id: I5bd41e2edbf874ce8e2f5662709f31143be8f1c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6605724
Reviewed-by: Kevin Ellis <kevers@chromium.org>
Commit-Queue: David Awogbemila <awogbemila@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1469239}