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];
```

{toIndex: update.toIndex, content: update.content.toString()}
            );
          }
          break;
        case ReactMultiChildUpdateTypes.MOVE_EXISTING:
          moveChild(
            parentNode,
            update.fromNode,
            getNodeAfter(parentNode, update.afterNode)
          );
          if (__DEV__) {
            ReactInstrumentation.debugTool.onNativeOperation(
              parentNodeDebugID,
              'move child',
              {fromIndex: update.fromIndex, toIndex: update.toIndex}
            );
          }
          break;
        case ReactMultiChildUpdateTypes.SET_MARKUP:
          setInnerHTML(
            parentNode,
            update.content
          );
          if (__DEV__) {
            ReactInstrumentation.debugTool.onNativeOperation(
              parentNodeDebugID,
              'replace children',
              update.content.toString()
            );
          }