This is a bug report.

**Expected Behavior**
React should not suggest me to download the DevTools extension in a `chrome-extension://` page, because the extension has no permission to inject the devtool.

**Actual Behavior**
`Download the React DevTools and use an HTTP server (instead of a file: URL) for a better development experience: https://fb.me/react-devtools`

**Reproducing**

1. Create a Chrome extension with an `option` or `popup` page that uses React
2. Load the extension to Chrome and open up that page.
3. Observe console.

**Version**
Google Chrome 56.0.2924.3
React 15.4.0

textInstance: TextInstance,
    oldText: string,
    newText: string,
  ): void {
    textInstance.nodeValue = newText;
  },
  appendChild(parentInstance: Instance, child: Instance | TextInstance): void {
    parentInstance.appendChild(child);
  },
  appendChildToContainer(
    container: Container,
    child: Instance | TextInstance,
  ): void {
    if (container.nodeType === COMMENT_NODE) {
      (container.parentNode: any).insertBefore(child, container);
    } else {
      container.appendChild(child);
    }
  },
  insertBefore(
    parentInstance: Instance,
    child: Instance | TextInstance,
    beforeChild: Instance | TextInstance,
  ): void {
    parentInstance.insertBefore(child, beforeChild);
  },
  insertInContainerBefore(
    container: Container,
    child: Instance | TextInstance,
    beforeChild: Instance | TextInstance,