Merge "Update back arrow panel dimensions." into tm-dev am: 3f32ba87 am: fc2c8ad1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17574629



Change-Id: I80230d3c9e3f06f48889243c70b7439c63e39836
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>