Nuke TimelineAllEventsReceived event

BUG=403684,398785
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/476773002

git-svn-id: svn://svn.chromium.org/blink/trunk@180349 bbb929c8-8fbe-4397-9dbb-9b2b20218538