Added D-Bus constants used by arc-oemcrypto.

This is to use with the D-Bus service in:
https://chrome-internal-review.googlesource.com/c/407752

BUG=b:62576653
TEST=none

Change-Id: Iaa612f1f7400a68c54a915c1ae3408838f520464
Reviewed-on: https://chromium-review.googlesource.com/609080
Commit-Ready: Jeffrey Kardatzke <jkardatzke@google.com>
Tested-by: Jeffrey Kardatzke <jkardatzke@google.com>
Reviewed-by: Dan Erat <derat@chromium.org>
Reviewed-by: Jeffrey Kardatzke <jkardatzke@google.com>
1 file changed