[automerger skipped] [DO NOT MERGE] Animate dialog stack and use in UserSwitcher am: 327d67cb am: eade04db -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16244707

Change-Id: I4fe6493a5f9e38e5ccd73326c0b9d7e232542ce5