Share TO Jasonette App

I would like to be able to share a PDF document (for example received by email) to a Jasonette App.
Is that possible?
So far I just found the possibility to share things from a Jasonette App using the `$util.share` action but I haven't found a solution for the other way around.

Start by reviewing how Android handles sharing a PDF from email into another app, then compare that flow with the existing `$util.share` action mentioned in the issue. Define the supported incoming-share behavior and confirm it works for a PDF received by email; the issue does not name any files or tests.

Written by the indexing model from the issue text.