* Simplify StateManagerDisk implementation
* Act more like the memory state manager and only track the root state in self.states
* .load_state always loads a single state or returns None
* .populate_states is the new entry point in loading from disk and it only occurs
when the root state is not known
* much fast
* StateManagerDisk now acts much more like StateManagerMemory
Treat StateManagerDisk like StateManagerMemory for AppHarness
* Handle root_state deserialized from disk
In this case, we need to initialize the whole state tree, so any non-persistent
states will still get default values, whereas on-disk states will overwrite the
defaults.
* Cache root_state under client_token for StateManagerMemory compatibility
Mainly this just makes it easier for us to write tests that work against either
Disk or Memory state managers.
aa69234b76