* Extract common code of ChooseLockPassword.SaveAndFinishWorker and
ChooseLockPattern.SaveAndFinishWorker to the parent class.
* Make setters return this to make it easy to chain setter calls.
* Rename SaveChosenLockWorkerBase to SaveAndFinishWorker.
This will make the code changes in the next CL much easier.
Bug: 271968977
Bug: 277561275
Test: 1. Add screen lock (password/PIN/pattern) using Settings
2. check screen lock works correctly
Change-Id: I98acd25f2dd81ab4608cc6943e4f238070003c17