Calling `ReactDefaultPerf.printWasted()` results in:

```
Uncaught TypeError: Cannot read property 'forEach' of undefined
writes.(anonymous function).forEach @ ReactDefaultPerfAnalysis.js:195
Object.keys.forEach @ ReactDefaultPerfAnalysis.js:192
getUnchangedComponents @ ReactDefaultPerfAnalysis.js:191
getInclusiveSummary @ ReactDefaultPerfAnalysis.js:139
ReactDefaultPerf.getMeasurementsSummaryMap @ ReactDefaultPerf.js:118
ReactDefaultPerf.printWasted @ ReactDefaultPerf.js:133
```

(this is on a page internally at Facebook so I assume it's a fairly recent React version)

}
    React = require('React');
    ReactDOM = require('ReactDOM');
    ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
    ReactDefaultPerf = require('ReactDefaultPerf');
    ReactTestUtils = require('ReactTestUtils');
    ReactDefaultPerfAnalysis = require('ReactDefaultPerfAnalysis');
    App = React.createClass({
      render: function() {
        return <div><Box /><Box flip={this.props.flipSecond} /></div>;
      },
    });
    Box = React.createClass({
      render: function() {
        return <div key={!!this.props.flip}><input /></div>;
      },
    });
    
    Div = React.createClass({
      render: function() {
        return <div {...this.props} />;
      },
    });
  });
  afterEach(function() {
    if (console.table.isFake) {
      delete console.table;
    }
  });
  function measure(fn) {