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)

ReactDOM.render(<Div>hey</Div>, container);
    });
  });
  it('should not count raw HTML update as waste', function() {
    var container = document.createElement('div');
    ReactDOM.render(
      <Div dangerouslySetInnerHTML={{__html: 'me'}} />,
      container
    );
    expectNoWaste(() => {
      ReactDOM.render(
        <Div dangerouslySetInnerHTML={{__html: 'you'}} />,
        container
      );
    });
  });
  it('should not count child reordering as waste', function() {
    var container = document.createElement('div');
    ReactDOM.render(<Div><div key="A" /><div key="B" /></Div>, container);
    expectNoWaste(() => {
      ReactDOM.render(<Div><div key="B" /><div key="A" /></Div>, container);
    });
  });
  it('should not count text update as waste', function() {
    var container = document.createElement('div');
    ReactDOM.render(<Div>{'hello'}{'world'}</Div>, container);
    expectNoWaste(() => {
      ReactDOM.render(<Div>{'hello'}{'friend'}</Div>, container);
    });
  });