title: Getting the video url during WebView onShowCustomView under KitKat
body: <p>I have been using <code>onShowCustomView</code> in order to get the url of the playing video inside a WebView. I was using <code>HTML5VideoFullScreen$VideoSurfaceView</code> and getting the "mUri" field but now it seems like the frame has changed to <code>ContentVideoView$VideoSurfaceView</code> and I don't see an "mUri" there. Does anyone know where to get that url on kitkat?</p>
  
  <p>Thanks.</p>