bug

Warning displayed in console about internal error of React performance measurement code.

``` js
import React from 'react';
import { render } from 'react-dom';
import Perf from 'react-addons-perf';
import { browserHistory, Router } from 'react-router';

import routes from './routes';
import persist from 'altFlux/persist';

persist('docs');

const target = document.getElementById('app');

Perf.start();

render(
  <Router
    routes={routes}
    history={browserHistory}
  />,
  target,
  () => {
    Perf.stop();
    Perf.printWasted();
  }
);
```

![screen shot 2016-05-23 at 9 21 08 am](https://cloud.githubusercontent.com/assets/91464/15472297/5e440d48-20c8-11e6-99d7-363f6d1bdcce.png)

15.1.0
Google Chrome

checkDebugID(debugID);
    emitEvent('onSetChildren', debugID, childDebugIDs);
  },
  onSetOwner(debugID, ownerDebugID) {
    checkDebugID(debugID);
    emitEvent('onSetOwner', debugID, ownerDebugID);
  },
  onSetParent(debugID, parentDebugID) {
    checkDebugID(debugID);
    emitEvent('onSetParent', debugID, parentDebugID);
  },
  onSetText(debugID, text) {
    checkDebugID(debugID);
    emitEvent('onSetText', debugID, text);
  },
  onMountRootComponent(debugID) {
    checkDebugID(debugID);
    emitEvent('onMountRootComponent', debugID);
  },
  onBeforeMountComponent(debugID, element) {
    checkDebugID(debugID);
    emitEvent('onBeforeMountComponent', debugID, element);
  },
  onMountComponent(debugID) {
    checkDebugID(debugID);
    emitEvent('onMountComponent', debugID);
  },
  onBeforeUpdateComponent(debugID, element) {