Revert "Lists returned from OS aren't mutable."

This reverts commit 97449fa389dbc1ab872d63fde001bae7a659991b.

Bug: 33034458
Bug: 33032977
Bug: 27856974
Change-Id: If913e587ce4a48b9ed1c7c0a811bc39ce4e31d3c
2 files changed