Migrate BP <odl:action-provider> for PacketProcessingService from XML to programmatic blueprint wiring

The only remaining open loose end of OPNFLWPLUG-1046 is this pesky little business:

org.opendaylight.genius.arputil.internal.ArpUtilImpl and org.opendaylight.genius.ipv6util.nd.Ipv6NsHelper, and possibly other places, require an OFP PacketProcessingService @Inject-ed.

In our OSGi Karaf BP environment, this works via an <odl:rpc-service> in OSGI-INF/blueprint/arputil.xml and /OSGI-INF/blueprint/ipv6util.xml, which from what I gathered is provided by the org.opendaylight.openflowplugin.impl.services.sal.PacketProcessingServiceImpl that is registered as an <odl:action-provider> in OSGI-INF/blueprint/openflowplugin-impl.xml.

What is an odl:action-provider? How does it obtain the RequestContextStack (of which there are several implementations), DeviceContext (apparently created by DeviceManagerImpl.createContext from a ConnectionContext) and ConvertorManager (looks easy) which it requires?