Summary:
Starting a screencapture longer than 30 seconds would timeout as the start command waits for the process to finish. Removed that wait is it is the stop command that should only wait for the finish.
(n.b. please ship after accepting, as I'm on PTO)
Reviewed By: LukeDefeo
Differential Revision: D38918570
fbshipit-source-id: fd93e1239985c81a2143ceb79312518e7ebb27f5
dab510c546