Add freon support in security_AccountsBaseline

Split x11 & freon specific users & groups into new files.

For freon, remove references to the xorg user & group, and allow chronos
in input (in the short term - we need to rework this).

BUG=chromium:413140
TEST=ran security_AccountsBaseline on link & link_freon
CQ-DEPEND=CL:225945

Change-Id: I929ddfef6e2ed9a6e78875c2e509329c04bde4a1
Reviewed-on: https://chromium-review.googlesource.com/225946
Commit-Queue: Michael Spang <spang@chromium.org>
Tested-by: Michael Spang <spang@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
7 files changed