syncing. This provides a key-value store, per folder, that
can be used by network Stores to record persistent data such
as sync status, server keys, etc.
Note that, by definition, this only applies to remote folders
(e.g. IMAP, POP3). You'll see everywhere that LocalFolder is
passed null, and this is correct - LocalFolder *is* persistent
storage and does not need external help.
Note to reviewers: The core changes are Folder.java,
LocalStore.java, and LocalStoreUnitTests.java, so please give
them the bulk of your reviewer attention. The other files
are just following along with minor API changes. Of those,
the one worth close examination is MessagingController.java,
which is the only place in the system where remote Folders
are bonded with Local Folders and thus where this new API
comes into play.
Note to jham: Can you please take a look at
LocalStore.LocalFolder.setPersistentString() and recommend
better SQL foo than my primitive test-then-update-or-insert
logic, which is not transactional or threadsafe.
BUG=1786939
Automated import of CL 146134
c6039f7d17