title: SFSafariViewController: open file protected with OAuth
body: <p>I need to display a <code>PDF</code> file stored on the server and protected with the OAuth scheme (i.e. the client should sent the token with each request).</p>
  
  <p>I'd also would like to have the share button available, which comes by default with <code>SFSafariViewController</code>. Is there any way to add a custom authorization header to the <code>SFSafariViewController</code>'s request? Or the only way to achieve the aforementioned behavior is to create a custom <code>UIViewController</code> with <code>WKWebView</code> as it's <code>view</code>?</p>