Merge "Only run Animation#setBackdropColor on overriden app transition" into tm-dev am: 2b70f83f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17983851



Change-Id: I87c07eee7c8c6b92b296f78c9504d713793abccb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>