#import <DOM/Node.idl>

[Exposed=Window, UseNewAKString]
interface CustomElementRegistry {
    [CEReactions] undefined define(DOMString name, CustomElementConstructor constructor, optional ElementDefinitionOptions options = {});
    (CustomElementConstructor or undefined) get(DOMString name);
    Promise<CustomElementConstructor> whenDefined(DOMString name);
    [CEReactions] undefined upgrade(Node root);
};

callback CustomElementConstructor = HTMLElement ();

dictionary ElementDefinitionOptions {
    DOMString extends;
};