Add an option to allow disk syncing to be turned off

Bug: 27795746

Change-Id: I47447a8467c409db526483ac7e4a9394cd68578a
(cherry picked from commit fd9b918d2e49de4b7b7568aaa39f7e179752766d)
(cherry picked from commit 2c2deeb032f6c158cf4f782e1765a4a21af88cb3)
3 files changed