We're switching Atom to React, but we want to support backward-compatible shims to our previous view framework.

In the old framework, views were represented as jQuery-wrapped DOM elements. Ideally, we'd like to provide backward-compatible shims by simply rendering the React component and wrapping its root element in a jQuery wrapper with an API that's compatible to our old editor views. That would essentially look like this:

``` javascript
var editorRoot = document.createElement('div')
React.renderComponentWithRootElement(Editor(props), editorRoot)

// the element would actually be wrapped in a custom subclass of jQuery,
// but this is clearer for this example
var editorShim = $(editorRoot) 
```

Currently, this isn't possible because React components need to be rendered into a container. So instead we need to create a wrapper element and render the component inside it. This is sad because it adds an extra layer of markup which confuses styling, and also means that the editor has a wrapper when used via the shim layer but no wrapper when embedded as a child via React itself.

Is there something fundamental preventing React from adopting DOM nodes directly without the parent? Is this something we could even hack in in a way that would be somewhat maintainable?

:heart:

'%s received a final argument during this render, but not during ' +
        'the previous render. Even though the final argument is optional, ' +
        'its type cannot change between renders.',
      currentHookNameInDev,
    );
    return false;
  }
  
  
  if (nextDeps.length !== prevDeps.length) {
    warning(
      false,
      'The final argument passed to %s changed size between renders. The ' +
        'order and size of this array must remain constant.\n\n' +
        'Previous: %s\n' +
        'Incoming: %s',
      currentHookNameInDev,
      `[${nextDeps.join(', ')}]`,
      `[${prevDeps.join(', ')}]`,
    );
  }
  for (let i = 0; i < prevDeps.length && i < nextDeps.length; i++) {
    if (is(nextDeps[i], prevDeps[i])) {
      continue;
    }
    return false;
  }
  return true;
}
class Updater {