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];
```

ReactDOMComponentTree.precacheNode(instance, rootElement);
        return;
      } else {
        var checksum = rootElement.getAttribute(
          ReactMarkupChecksum.CHECKSUM_ATTR_NAME
        );
        rootElement.removeAttribute(ReactMarkupChecksum.CHECKSUM_ATTR_NAME);
        var rootMarkup = rootElement.outerHTML;
        rootElement.setAttribute(
          ReactMarkupChecksum.CHECKSUM_ATTR_NAME,
          checksum
        );
        var normalizedMarkup = markup;
        if (__DEV__) {
          
          
          
          
          var normalizer;
          if (container.nodeType === ELEMENT_NODE_TYPE) {
            normalizer = document.createElement('div');
            normalizer.innerHTML = markup;
            normalizedMarkup = normalizer.innerHTML;
          } else {
            normalizer = document.createElement('iframe');
            document.body.appendChild(normalizer);
            normalizer.contentDocument.write(markup);
            normalizedMarkup = normalizer.contentDocument.documentElement.outerHTML;
            document.body.removeChild(normalizer);
          }