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];
```

ReactCurrentOwner.current == null,
      '_renderNewRootComponent(): Render methods should be a pure function ' +
      'of props and state; triggering nested component updates from ' +
      'render is not allowed. If necessary, trigger nested updates in ' +
      'componentDidUpdate. Check the render method of %s.',
      ReactCurrentOwner.current && ReactCurrentOwner.current.getName() ||
        'ReactCompositeComponent'
    );
    invariant(
      container && (
        container.nodeType === ELEMENT_NODE_TYPE ||
        container.nodeType === DOC_NODE_TYPE ||
        container.nodeType === DOCUMENT_FRAGMENT_NODE_TYPE
      ),
      '_registerComponent(...): Target container is not a DOM element.'
    );
    ReactBrowserEventEmitter.ensureScrollValueMonitoring();
    var componentInstance = instantiateReactComponent(nextElement);
    if (__DEV__) {
      
      
      componentInstance._debugID = 0;
    }
    
    
    
    ReactUpdates.batchedUpdates(
      batchedMountComponentIntoNode,
      componentInstance,
      container,