[automerger skipped] Add developer option for back animation DO NOT MERGE am:...

[automerger skipped] Add developer option for back animation DO NOT MERGE am: 94f506aa am: d67d6753 am: 33ebed72 am: 7a8d34aa -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17619727



Change-Id: Icf415eed42e0a390dd02102d229514b7352eeb6f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>