TIF: Revisit types in TvInputInfo and TvContract.Channels.

For the types in TvInputInfo, TYPE_TUNER represents all the TV inputs
having channels in TvProvider. Also, String is used for the types in
TvContract.Channels for further extension.

Change-Id: Iee1163b449d9f9723ff665178f2967bb8c0ad71d
6 files changed