TIF: cosmetic changes for consistency.

- Remove uncessarry logic in buildTvInputListLocked().
  (No longer needed because we removed availability.
   Verified the bug case, b/15738607, does not happen without this logic.)
- Rename member variables in XXXState classes.
- Define SessionCallback for consistency.

Change-Id: I49642c909ad7f77d97d1d90670c7bb7c2b12cda8