Merge "DO NOT MERGE New back affordance small polish nits" into tm-qpr-dev am: 2f49f787c8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21483766

Change-Id: I09f5a77cf1db89d6cc2346692f383b01efaa4911
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>