onFullScreenInit : Phaser.Signal
This signal is dispatched when fullscreen mode is ready to be initialized butbefore the fullscreen request. The signal is passed two arguments: scale (the ScaleManager), and an object in the form {targetElement: DOMElement}. The targetElement is the fullScreenTarget element,if such is assigned, or a new element created by createFullScreenTarget. Custom CSS styling or resets can be applied to targetElement as required. If targetElement is not the same element a