1. Ungrant did not check the callers uid which allowed any caller
to remove grants to any key.
2. Grants were not removed when a key was deleted.
3. clean_uid did not clear the grant cache of the target uid.
This would leave state grants that could have been used
by a new app that happend to get the same uid as the one
that was previously uninstalled.
4. Various paths did not respect grants: del, exist, getmtime
The del path was particularly awkward because it is required
by upgradeKeyBlob. This means it must work when a key that needs
upgrading is accessed through a grant alias.
Bug: 65851049
Change-Id: I6709b7562d47ad6156bee88a9e2d961f8a4a797d
This CL isn't nearly as big as it looks. It doesn't change keystore
functionality, it just moves all of the classes out of the former
keystore.cpp into their own .h and .cpp files.
Note that this is a cherry-pick from:
https://android-review.googlesource.com/#/c/194971
Change-Id: Ide326c4f1d03984994d1bd9a76fa68d37da230dc
