Move testRunner.toggleCapsLock() to uiController as uiController is the preferred JavaScript object for UI test functions. Having this functionality be on uiController makes it an asynchronous function naturally and complements use of onkeydown, onkeyup listeners to know when the Caps Lock key event is dispatched. It also facilitates its use directly as part of scripts with other uiController functions invocations that are passed in a single invocation of testRunner.runUIScript().