base

Add measurement API to DefaultContainerService

System applications that don't have "media_rw" access need some way to
measure the size of directories on the SD card and other internal media.
Add this API to DefaultContainerService so they can simply bind to the
service and make an RPC.

Bug: 3203974
Change-Id: I4e1bcd7a1b702b156c011ecc04f6915022cb258a