[automerger skipped] Only allow trusted overlays to specify FLAG_SLIPPERY am: 07e7aaff29 am: c7052c9c79 -s ours

am skip reason: Merged-In Ia30f1c38d5ddb351c90b748ea76448a76a9dde7b with SHA-1 07e7aaff29 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16241253

Change-Id: I973210801594085c5d890a558cbb7b403b47f86f