DO NOT MERGE New back affordance small polish nits am: 92e8dafec8

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

Change-Id: I0a72d025dc0e18c2eefe2f5e5a53a3197f3b4630
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>