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)

'{"node":"<not serializable>","children":[],"html":null,"text":null}' :
        '"<div data-reactroot=\\"\\" data-reactid=\\"1\\">hey</div>"',
    }]);
  });
  it('warns once when using getMeasurementsSummaryMap', function() {
    var measurements = measure(() => {});
    spyOn(console, 'error');
    ReactDefaultPerf.getMeasurementsSummaryMap(measurements);
    expect(console.error.calls.length).toBe(1);
    expect(console.error.argsForCall[0][0]).toContain(
      '`ReactPerf.getMeasurementsSummaryMap(...)` is deprecated. Use ' +
      '`ReactPerf.getWasted(...)` instead.'
    );
    ReactDefaultPerf.getMeasurementsSummaryMap(measurements);
    expect(console.error.calls.length).toBe(1);
  });
  it('warns once when using printDOM', function() {
    var measurements = measure(() => {});
    spyOn(console, 'error');
    ReactDefaultPerf.printDOM(measurements);
    expect(console.error.calls.length).toBe(1);
    expect(console.error.argsForCall[0][0]).toContain(
      '`ReactPerf.printDOM(...)` is deprecated. Use ' +
      '`ReactPerf.printOperations(...)` instead.'
    );
    ReactDefaultPerf.printDOM(measurements);
    expect(console.error.calls.length).toBe(1);
  });
});