Merge "[Media TTT] Refactor media states to use an enum instead of sealed...

Merge "[Media TTT] Refactor media states to use an enum instead of sealed classes." into tm-dev am: bb1a04a5 am: 74ec8b50

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17070719

Change-Id: I87f3ee65cdbbc6dbd25a4e609626e82c624fdc68