This test: fast/animation/css-animation-resuming-when-visible-with-style-change2.html is highly flakey after https://trac.webkit.org/changeset/235948/webkit confirmed flakiness using command: run-webkit-tests --root testbuild-235948 fast/animation/css-animation-resuming-when-visible-with-style-change2.html --iterations 100 -f running this command on r235947 yields no failures. History: https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=fast%2Fanimation%2Fcss-animation-resuming-when-visible-with-style-change2.html Diff: https://build.webkit.org/results/Apple%20High%20Sierra%20Release%20WK2%20(Tests)/r235973%20(6728)/fast/animation/css-animation-resuming-when-visible-with-style-change2-pretty-diff.html
Issue appears resolved as of https://trac.webkit.org/changeset/235983/webkit closing bug.
<rdar://problem/44473645>