Add PartitionUpdateGenerator am: d3865d1bc4 am: 123742b9bd am: 5d27d4869d am: 96aa0c34a4 am: 2e5aa38700

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

Change-Id: I85708c2e29becacde9a614b5c32a9a5220ea15a8