Merge "When detaching player, set to null before clean-up" into udc-dev am: 61c04730

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22752080



Change-Id: Idf904a3a6062739ee3324a3ee7576b435ff7e766
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>