Fix for loading progress for mapped files. am: 6405bab34a am: b59775afc2 am: 7aa80337ab

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/incremental_delivery/+/15787414

Change-Id: Iadb56a17eae2ffb3ed4f4cae49685b83b580393c