Merge "Make ClockRegistry and its provider singleton" into udc-dev am: df602e63

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/23482074



Change-Id: I96f7a589d128f3b794d4c559709a547295356986
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>