TvInputManagerService now creates an InputChannel pair and passes one
end to the app and the other end to the service. Then the TvInputManager
in the app creates an InputEventSender around one end of the channel to
send events and the service creates an InputEventReceiver around the
other end of the channel to receive events.
Most of the newly added code here was borrowed heavily from the IME.
Change-Id: I0bd83847cba0033ccb6f4b6dad267ebeaf5e9c7c
6a6059a29e