Programatically enable/disable pinch to zoom on WKWebView and viewForZoomingInScrollView
<p>I have a WKWebView and I want to programatically enable/disable pinch to zoom. </p>

<p>What should I return when I want to enable pinch to zoom? </p>

<p>wkWebView!.scrollView breaks with </p>

<blockquote>
  <p>'The view returned from viewForZoomingInScrollView: must be a subview
  of the scroll view. It can not be the scroll view itself.'</p>
</blockquote>

<pre><code>func viewForZoomingInScrollView(scrollView: UIScrollView) -&gt; UIView? {

  if pinchToZoom {
    return ???
  } else {
    return nil
  }
}
</code></pre>