Merge "Add @Nullable to BluetoothAdapter provider." into tm-qpr-dev am: f1f50ee2 am: a279e614

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20814153



Change-Id: Iee1e877ca407fe2137c59848be06a2009c70c10e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>