We don't use rAF for scheduling anything anymore, yet we still enable it in ReactDOMFrameScheduling. It can probably be simplified a bit by not exposing it.
}
      : function() {
          
          return frameDeadline - Date.now();
        },
  };
  
  var messageKey = '__reactIdleCallback$' + Math.random().toString(36).slice(2);
  var idleTick = function(event) {
    if (event.source !== window || event.data !== messageKey) {
      return;
    }
    isIdleScheduled = false;
    var callback = scheduledRICCallback;
    scheduledRICCallback = null;
    if (callback) {
      callback(frameDeadlineObject);
    }
  };
  
  
  window.addEventListener('message', idleTick, false);
  var animationTick = function(rafTime) {
    isAnimationFrameScheduled = false;
    var nextFrameTime = rafTime - frameDeadline + activeFrameTime;
    if (
      nextFrameTime < activeFrameTime &&
      previousFrameTime < activeFrameTime
    ) {
      if (nextFrameTime < 8) {