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

) {
    invariant(
      parentComponent != null && ReactInstanceMap.has(parentComponent),
      'parentComponent must be a valid React Component',
    );
    return renderSubtreeIntoContainer(
      parentComponent,
      element,
      containerNode,
      false,
      callback,
    );
  },
  unmountComponentAtNode(container: DOMContainer) {
    invariant(
      isValidContainer(container),
      'unmountComponentAtNode(...): Target container is not a DOM element.',
    );
    if (container._reactRootContainer) {
      if (__DEV__) {
        const rootEl = getReactRootElementInContainer(container);
        const renderedByDifferentReact =
          rootEl && !ReactDOMComponentTree.getInstanceFromNode(rootEl);
        warning(
          !renderedByDifferentReact,
          "unmountComponentAtNode(): The node you're attempting to unmount " +
            'was rendered by another copy of React.',
        );
      }