I was testing latest refactor of PerfTools.
When using printOperations() often (but not always) I get 

```
Uncaught TypeError: Cannot read property 'displayName' of undefined
```

in getOperations() on the line:

```
var {displayName, ownerID} = treeSnapshot[instanceID];
```

)).toBe('checked=""');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'checked',
        false
      )).toBe('');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'scoped',
        true
      )).toBe('scoped=""');
    });
    it('should create markup for booleanish properties', function() {
      expect(DOMPropertyOperations.createMarkupForProperty(
        'download',
        'simple'
      )).toBe('download="simple"');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'download',
        true
      )).toBe('download=""');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'download',
        'true'
      )).toBe('download="true"');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'download',
        false
      )).toBe('');
      expect(DOMPropertyOperations.createMarkupForProperty(
        'download',
        'false'