service_constants: Added constant for IsUsbguardEnabled dbus method.

This constant denotes a dbus method that will be used to query
whether USBGuard should be enabled at the lock screen.

BUG=None
TEST=Check that go/crosr/1154427 compiles

Change-Id: Ifc99845f649df732e562cbfe3ff783ede21b125f
Signed-off-by: Allen Webb <allenwebb@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1154326
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
1 file changed