* Guarantee that up to 16 Account (with HostAuths), and Policy rows
are always cached. Also, 6 commonly used Mailboxes per Account
(Inbox, Outbox, Drafts, Sent, Trash, and Search)
* Precache these rows when EmailProvider starts up
* Ensure that newly added, precachable rows are cached when created
* Clean up some inefficient/wrong caching code
* Fix a commonly called method in NotificationManager in which we
load a single Mailbox row using selection vs withAppendedId
* Confirm that we don't read from the database in typical use and
heavy message loading
* Add a special URI for finding mailbox by type (using the cache)
* Add special-case code for EmailContent.count(Account.CONTENT_URI)
which is used in a number of places (including on the UI thread)
and whose value is easily determined
* Add a special URI to get the default account id
* Confirm that all unit tests work
The goal here is to be able to load all Account, HostAuth, Policy,
and Mailbox objects (by id) without worrying about disk access.
There will still be a single disk read for uncommon Mailbox reads,
but this should be considered acceptable.
Change-Id: Ibc9aa7acc73185e360b0b6f3053b90a985e97210
TODO: Unit tests
6e418aa41a