Clarify code to auto-show subtitles
Clarify code to auto-show subtitles

Vaguely relates to the investigation into issue #1696

Change-Id: I5d16f5cbdabf72361598e28bff196a5be7030967

tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player