[Media TTT] Use a listener pattern to notify about view removals. am: 5a7e9e6349 am: 7aecf7cda5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21020063

Change-Id: Ibe06261710cef967c195a0fea29833dc46e095a5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>