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];
```

return false;
    }
    return inst != null &&
           typeof inst.render === 'function' &&
           typeof inst.setState === 'function';
  },
  isCompositeComponentWithType: function(inst, type) {
    if (!ReactTestUtils.isCompositeComponent(inst)) {
      return false;
    }
    var internalInstance = ReactInstanceMap.get(inst);
    var constructor = internalInstance
      ._currentElement
      .type;
    return (constructor === type);
  },
  isCompositeComponentElement: function(inst) {
    if (!ReactElement.isValidElement(inst)) {
      return false;
    }
    
    
    var prototype = inst.type.prototype;
    return (
      typeof prototype.render === 'function' &&
      typeof prototype.setState === 'function'
    );
  },