virtual/threaded/animations/play-state-initially-paused.html is failing.

BUG=392706
TBR=eae@chromium.org

Review URL: https://codereview.chromium.org/381583006

git-svn-id: svn://svn.chromium.org/blink/trunk@177792 bbb929c8-8fbe-4397-9dbb-9b2b20218538