title: Add "Open in iBooks" to UIWebView
body: <p>I am developing a wrapper application for a site. Basically, it opens mobile version of a site in UIWebView. Some links on the site point to PDFs.</p>
  
  <p>When the same site is opened in Safari and a link to PDF is tapped a nice black stripe with "Open in iBooks" is shown over the PDF. Like on the picture below:</p>
  
  <p><img src="https://i.stack.imgur.com/NUqdQ.png" alt="enter image description here"></p>
  
  <p>How could I implement the same looking stripe in my app?</p>
  
  <p>EDIT:</p>
  
  <p>I am <em>not</em> asking about how to create a black button on translucent background. </p>
  
  <p>I am interested in reproducing the whole workflow:</p>
  
  <ul>
  <li>User navigates to a PDF</li>
  <li>A stripe (view) popups <strong>if and only if</strong> there is iBooks app (or any other PDF viewer) installed.</li>
  <li>Tapping a button in popup transfers document to that app and the app opens.</li>
  </ul>