Function drive 

pub fn drive(harness: &mut FrameHarness, steps: &[Step]) -> Outcome

Run steps against the app harness hosts and answer what it shows.

Each step runs through the path --headless-drive runs it on, and the harness is left where the last step put it, so the caller keeps driving it or closes it as it would after a CLI run. A step that fails ends the drive: the steps after it would run against state the failed one never produced, and the record names the one that stopped it.