[automerger skipped] Merge "Make UserTrackerImpl use UserSwitchObserver instead of broadcast." into tm-qpr-dev am: 8fd6cb70f0 am: 3f4ad56c96 -s ours

am skip reason: Merged-In Ica2be8cc434cea4bb526a51eeb8171765f461172 with SHA-1 f5c2a5261d is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21024523

Change-Id: Ie5ad5c93b0a7f6a7106d874a068c324ea8f56a85
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>