get() {
      return this[privateProp]
    }
@static
Define a property name as an event handler for a given Facade class, so that it
automatically updates the global event registry when set.
@param {class} facadeClass - the class whose prototype the property should be defined on
@param {String} propName - the name of the event handler property, e.g. 'onMouseOver'
@param {String} eventType - the type of the event that will trigger the handler, e.g. 'mouseover'