LayoutTests/imported/w3c/web-platform-tests/interfaces/hr-time.idl

typedef double DOMHighResTimeStamp;

[Exposed=(Window,Worker)]
interface Performance : EventTarget {
    DOMHighResTimeStamp now();
    readonly attribute DOMHighResTimeStamp timeOrigin;
    [Default] object              toJSON();
};

partial interface WindowOrWorkerGlobalScope {
    [Replaceable]
    readonly attribute Performance performance;
};