Drop libevent as a //base dependency on Mac.

After c96c632d5501d5ebba14e1130fdea8b15ac29756, MessagePumpKqueue is
used instead to drive IO MessageLoops. The MessagePumpLibevent has gone
unused, and the dependency can now be dropped.

Bug: 973882
Change-Id: I698749a2dedea216bc8fa04578079f3e7b99294d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1675913
Reviewed-by: Fran├žois Doray <fdoray@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672151}
1 file changed