Remove the include "core/events/ThreadLocalEventNames.h"

Only EventTarget.h needs this include

This is a follow up patch for this CL by Adam Barth
https://codereview.chromium.org/26890003

BUG=

Review URL: https://codereview.chromium.org/210133002

git-svn-id: svn://svn.chromium.org/blink/trunk@169950 bbb929c8-8fbe-4397-9dbb-9b2b20218538