Combine RecentsViewStateController with base class

- BaseRecentsViewStateController is only inherited by RecentsViewStateController, remove the base class to simplify code
- Also converted RecentsViewStateController to Kotlin and remove a bunch of warnings

Fix: 387267938
Test: presubmit and manual
Flag: EXEMPT refactor
Change-Id: I18e9c2b186a64a0af39230cb41e3b3f4949107d5