Layout Test legacy-animation-engine/animations/animation-callback-timestamp.html is a flaky failure

[Ryan Haddad]

The following layout test is failing on macOS

legacy-animation-engine/animations/animation-callback-timestamp.html

Probable cause:

This test was added in https://trac.webkit.org/changeset/230471/webkit

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=legacy-animation-engine%2Fanimations%2Fanimation-callback-timestamp.html

--- /Volumes/Data/slave/highsierra-debug-tests-wk2/build/layout-test-results/legacy-animation-engine/animations/animation-callback-timestamp-expected.txt
+++ /Volumes/Data/slave/highsierra-debug-tests-wk2/build/layout-test-results/legacy-animation-engine/animations/animation-callback-timestamp-actual.txt
@@ -1,4 +1,6 @@
-PASS All the differences between requestAnimationFrame() callback timestamps and Performance.now() were within 3ms.
+requestAnimationFrame() timestamp = 235.00000000000003, window.performance.now() = 238.00000000000003
+requestAnimationFrame() timestamp = 486, window.performance.now() = 489
+FAIL Some of the requestAnimationFrame() callback timestamps were larger than Performance.now() by more than 3ms.
 PASS successfullyParsed is true
 
 TEST COMPLETE

[Ryan Haddad]

Marked test as flaky in https://trac.webkit.org/changeset/230503/webkit

[Antoine Quint]

This test is gone as of r258150, see bug 208815.

[Radar WebKit Bug Importer]

<rdar://problem/60238178>