Merge "Implement LauncherLayoutSnapshot pulled atom callback." into sc-v2-dev am: 8c8dc56495

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15685719

Change-Id: I031cd264a3631248e0c8e0a1a2d524e1720ba0e1