Merge "Fix the documentation of onTimeShiftGetCurrentPosition()"

         * seek to a position earlier than the start position.

         *

         * <p>For playback of a recorded program initiated by {@link #onTimeShiftPlay(Uri)}, the

         * start position is the time when playback starts. It does not change.

         * start position should be 0 and does not change.

         *

         * @see #onTimeShiftPlay(Uri)

         * @see #onTimeShiftResume()