Merge "New back affordance small polish nits" into udc-dev am: 55b6a24b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21775241



Change-Id: Ia3f870625594c95816f8688a3a2f529955d437e9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>