Summary: Ref T4310. Ref T3720. Partly, this makes it easier for users to understand login sessions. Partly, it makes it easier for me to make changes to login sessions for T4310 / T3720 without messing anything up.
Test Plan: {F101512}
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T3720, T4310
Differential Revision: https://secure.phabricator.com/D7954
