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.
},
      });
    });
    return 0;
  };
} else if (typeof requestAnimationFrame !== 'function') {
  invariant(
    false,
    'React depends on requestAnimationFrame. Make sure that you load a ' +
      'polyfill in older browsers.',
  );
} else if (typeof requestIdleCallback !== 'function') {
  
  var scheduledRAFCallback = null;
  var scheduledRICCallback = null;
  var isIdleScheduled = false;
  var isAnimationFrameScheduled = false;
  var frameDeadline = 0;
  
  
  
  var previousFrameTime = 33;
  var activeFrameTime = 33;
  var frameDeadlineObject = {
    timeRemaining: typeof performance === 'object' &&
      typeof performance.now === 'function'
      ? function() {
          
          
          return frameDeadline - performance.now();