Merge "Add a way to reset persistent letterbox positions." into udc-qpr-dev am: e8c4f268ab

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24526911

Change-Id: I44cdb8f0c5943d8169940dea83ccb2f32e634bb2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>