Remove libsystemd dependency and add --sd-notify flag.

Implement system notifications and introduce a flag that makes
it possible to specify the exact state to send to the daemon.

Bug: 826923
Change-Id: I4c077be4fbf145be2ced00cb843bbf8dce314645
Reviewed-on: https://chromium-review.googlesource.com/998761
Tested-by: David Reveman <reveman@chromium.org>
Reviewed-by: Stephen Barber <smbarber@chromium.org>
6 files changed