system_api: Add org.chromium.LockScreenService constants.

Add constants for a new org.chromium.LockScreenService D-Bus
service that will be exported by Chrome.

BUG=chromium:827680
TEST=built it

Change-Id: I71e6c03656e5f74b088f9f5473b4cd968ad338f7
Reviewed-on: https://chromium-review.googlesource.com/991454
Commit-Ready: Dan Erat <derat@chromium.org>
Tested-by: Dan Erat <derat@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
1 file changed