Merge "Early return when mA2dp is null (disconnected) to avoid null object reference" into udc-dev am: a8fcc09d3a am: 205e61b128

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23723003

Change-Id: Ib6416107ba5fd7dec1162b90ec234b86f5a13f42
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>