Merge "Use the LayoutManager as the source of truth for visible positions" into sc-dev am: 5cc44eb73e am: f492620c7d

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14800536

Change-Id: I7e3429c771529dc32ce4f646acf80b079dee1078