Merge "Check for null mLeash before setting alpha." into tm-dev am: 1f9afd72

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18585595



Change-Id: I52a1ced5b241c4b5236307333453b01591985b62
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>