<static> whenReady(handler, context, nonPrimer)
Add a device-ready handler and ensure the device ready sequence is started. Phaser.Device will not activate or initialize until at least one whenReady handler is added,which is normally done automatically be calling new Phaser.Game(..). The handler is invoked when the device is considered "ready", which may be immediatelyif the device is already "ready". See deviceReadyAt.
Parameters
Name Type Argument Default Description handler functi