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

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



Change-Id: I48d160147a144afd0a4352da89d7009826e4d54e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>