Add PartitionUpdateGenerator am: d3865d1bc4 am: 123742b9bd am: 5d27d4869d am: 96aa0c34a4

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1326712

Change-Id: I87a828b9b6936ed1f230ed14e510e4d42bff0e0d