[Web Animations] Positive delays of accelerated animations are not respected

[Antoine Quint]

Created attachment 349153 [details]
Test

See the attached test case, an animation with a delay does not respect it if it's accelerated:

document.body.appendChild(document.createElement("div")).animate({
    transform: ["translateX(100px)", "none"]
}, { duration: 1000, delay: 1000 });

[Antoine Quint]

<rdar://problem/44151416>

[Antoine Quint]

Created attachment 349306 [details]
Patch

[Antoine Quint]

Committed r235854: <https://trac.webkit.org/changeset/235854>

[Truitt Savell]

Looks like the new test added in: https://trac.webkit.org/changeset/235854/webkit

is flakey image failure: webanimations/accelerated-animation-with-delay-and-seek.html

History:
https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=webanimations%2Faccelerated-animation-with-delay-and-seek.html

Image:
https://build.webkit.org/results/Apple%20High%20Sierra%20Debug%20WK1%20(Tests)/r235865%20(5538)/webanimations/accelerated-animation-with-delay-and-seek-diffs.html

[Antoine Quint]

Reopening to attach new patch.

[Antoine Quint]

Created attachment 349880 [details]
Patch

[Antoine Quint]

Committed r236072: <https://trac.webkit.org/changeset/236072>