tree 7f6991fd6226553ffbe73ba519161a895f6732dd
parent 6770e23f2fe9741d7304c65c245426facb396d0a
author Anders Hartvoll Ruud <andruud@chromium.org> 1603900371 -0700
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1603905000 -0700

[scroll-animations] Handle changes to selector(#id) references

An @scroll-timeline rule may reference elements with selector(#id)
syntax. Whenever the element represented by the selector() function
changes, the "effective" CSSScrollTimeline produced by the
@scroll-timeline rule changes as well.

This CL solves this problem by registering IdTargetObservers
for the IDs a CSSScrollTimeline depends on. The IdTargetObservers
are registered when at least one Animation is attached, and
unregistered when the last Animation is detached. This is
similar to how the ScrollTimeline itself is registered/
unregistered with the resolved scroll source when Animations
attach/detach.

Marking the animation target elements for style recalc
(non-animation-style-change) means we'll re-evaluate the
@scroll-timeline rule against the current DOM state, and consider
whether or not we need a new CSSScrollTimeline for the animation.

Bug: 1074052
Change-Id: Iab0c6b8d8b57d7d63283e97355ee5d9948b831a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2356506
Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org>
Reviewed-by: Kevin Ellis <kevers@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821724}