The `setApkInternal` method had to infer the intent of the caller
based on the arguments which were passed on, and then do specific
things depending on the input. Instead, this change has three
distinct actions which can happen (add/remove/update). Each of
these methods does only one thing, and doesn't have to guess
the intent of the caller. The only exception may be "add", which
will (for convenience) delegate to "update" if it already knows
about the apk in question.
2ad61a4eb7