PathToLockId: Refactor to use a FunctionalInterface

Define a FunctionalInterface, and provide a static instance of
the converter. This allows to call it directly instead of getting
an instance injected.

Inspired-by: David Ostrovsky <david@ostrovsky.org>
Change-Id: I8d51c2989152672e3bbaae14c58f2973421c3732
3 files changed