Defer creating a GamepadController until a gamepad actually connects
(the first 'gamepadconnected' event, which the browser only fires once the
user has pressed a button on the pad). Returns a handle whose controller
field is filled once init runs (or stays null on a session that never sees
a pad). cancel() aborts a still-pending init.
Defer creating a GamepadController until a gamepad actually connects (the first
'gamepadconnected'event, which the browser only fires once the user has pressed a button on the pad). Returns a handle whosecontrollerfield is filled once init runs (or stays null on a session that never sees a pad).cancel()aborts a still-pending init.