The proximate goal is to eliminate dependencies on gwtorm's Key types.
This change starts a long series, first focusing on CompoundKey in
"leaf" keys in the key hierarchy, and working upwards from there.
Continue to use AutoValue classes even for keys that are just a single
value, to keep type signatures safer and more understandable when
multiple different key types are involved. For now, preserve the
convention of "get()" to get the single field, although this may be
revisited. Preserve the toString/parse behavior where necessary,
although that does not include the class in this change.
In the long term, we would also like to migrate the non-key "reviewdb"
classes away from gwtorm-ish patterns like making all fields mutable.
It's possible that this will also entail removing some key classes,
since they are no longer needed as keys in the gwtorm object model.
However, the first pass of refactoring series focuses on just key
classes.
Change-Id: I6982fb24ee18875c48c0119edbfea96888a1745b
9a2789e62e