Sync with latest styled media receiver bug fixes

Change-Id: I11fac3f653ec9991410ad3a6e4d175aa552de744
Update to sync with latest Styled Media Receiver bug fixes
Support for captions with MPL

Change-Id: I1f1c3c1281ae694f158826dc90fea17ed926898d
Update MPL to 1.0 and apply latest CLs related with code style.

Here are list of CLs applied.
- https://critique.corp.google.com/#review/81147584
- https://critique.corp.google.com/#review/81166272

Change-Id: Ie365af9508592be039bff1192c64b8367f938acd
Merge remote-tracking branch 'goog/master' into github_latest_update