[automerger skipped] Separate callbacks for dismiss start and end am: f0cd5dd1 -s ours

am skip reason: Merged-In I1ab46134b994cebff606345af62bf70f79a92e3f with SHA-1 11db9a36 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16988254

Change-Id: Ie4dc3992b7c8d9e59f3ac61119b767807aec5e79