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];
```

callback) {
    ReactMount.scrollMonitor(container, function() {
      ReactUpdateQueue.enqueueElementInternal(prevComponent, nextElement);
      if (callback) {
        ReactUpdateQueue.enqueueCallbackInternal(prevComponent, callback);
      }
    });
    return prevComponent;
  },
  /**
   * Render a new component into the DOM. Hooked by devtools!
   *
   * @param {ReactElement} nextElement element to render
   * @param {DOMElement} container container to render into
   * @param {boolean} shouldReuseMarkup if we should skip the markup insertion
   * @return {ReactComponent} nextComponent
   */
  _renderNewRootComponent: function(
    nextElement,
    container,
    shouldReuseMarkup,
    context
  ) {
    if (__DEV__) {
      ReactInstrumentation.debugTool.onBeginFlush();
    }
    
    
    
    warning(