dbus: login_manager: Add ARC method RemoveArcData

BUG=b:26784296
TEST=manually tested by diabling arc and verifying that files were
removed.

Change-Id: Idbc41253bc56d991ecc6fa6e2e88146306233a76
Reviewed-on: https://chromium-review.googlesource.com/343662
Commit-Ready: Dan Spaid <dspaid@chromium.org>
Tested-by: Dan Spaid <dspaid@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
1 file changed