Replace deferredUpdates usages

Summary:
The async mode unstable API deferredUpdates was removed in React 16.5.0 with
facebook/react#13488

As discussed there, the alternative workaround is to simply use requestIdleCallback or requestAnimationFrame.

Once a better API is released (tracking facebook/react#13306) we can use that instead for deferred async updates.

Reviewed By: hansonw

Differential Revision: D9814299

fbshipit-source-id: 8848cf05cd11ffba65b6d87233e2f5205121179b

Author: pelmers

modules/nuclide-commons-ui/HighlightedCode.example.js

@@ -10,8 +10,9 @@
  * @format
  */
 
+/* global requestAnimationFrame */
+
 import * as React from 'react';
-import ReactDOM from 'react-dom';
 import {Button} from './Button';
 import {HighlightedCode} from './HighlightedCode';
 
@@ -21,8 +22,8 @@ class HighlightedCodeExample extends React.Component<{}, {|count: number|}> {
   };
 
   _addOneMore = () => {
-    // $FlowIgnore
-    ReactDOM.unstable_deferredUpdates(() => {
+    // TODO(pelmers): Use react deferred update API when facebook/react/issues/13306 is ready
+    requestAnimationFrame(() => {
       // TODO: (wbinnssmith) T30771435 this setState depends on current state
       // and should use an updater function rather than an object
       // eslint-disable-next-line react/no-access-state-in-setstate