title: SFSafariViewController : Overlay is not appearing sometimes
body: <p>I am using SFSafariViewController, and as i did not wanted to show the status bar of safari and i have hidden it by adding a overlay. I have my own button on the overlay and its working fine. The safari status bar is hidden and it shows my overlay but somehow sometimes the overlay disappears and the safari status bar is visible. I doubt that its because the link is being reloaded automatically but how? I am only calling it once. I am not sure why overlay is disappear for sometimes only. below is my code - </p>
  
  <pre><code>self.navigationController?.presentViewController(sfController!, animated: true, completion: { 
              let bounds = UIScreen.mainScreen().bounds
              let overlay = UIView(frame: CGRect(x: 0, y: 0, width: bounds.size.width, height: 65))
              overlay.backgroundColor = UIColor(netHex: 0x275E37)
              let completedBtn = UIButton()
              let favBtn = UIButton()
  
              let image = UIImage(named: "home.png") as UIImage?
              let homeBtn   = UIButton(type: UIButtonType.Custom) as UIButton
              homeBtn.frame = CGRectMake(20, 25, 35, 35)
              homeBtn.setImage(image, forState: .Normal)
              homeBtn.addTarget(self, action: #selector(DetailsViewController.HomeBtnAction), forControlEvents:.TouchUpInside)
  
              completedBtn.setTitle("Mark as Completed",forState: .Normal)
              completedBtn.titleLabel!.font =  UIFont(name: "FidelitySans-Regular", size: 20)
              completedBtn.setTitleColor(UIColor.whiteColor(), forState: .Normal)
              completedBtn.frame = CGRectMake((bounds.size.width - 210), 25, 200, 35)
              completedBtn.backgroundColor = UIColor(netHex: 0x6F9824)
              completedBtn.addTarget(self, action: #selector(DetailsViewController.CompletedAction), forControlEvents: UIControlEvents.TouchUpInside)
  
              favBtn.setTitle("Save as Favorite", forState: .Normal)
              favBtn.titleLabel!.font =  UIFont(name: "FidelitySans-Regular", size: 20)
              favBtn.setTitleColor(UIColor.whiteColor(), forState: .Normal)
              favBtn.frame = CGRectMake((bounds.size.width - 420), 25, 200, 35)
              favBtn.backgroundColor = UIColor(netHex: 0x6F9824)
              favBtn.addTarget(self, action: #selector(DetailsViewController.FavoriteAction), forControlEvents: UIControlEvents.TouchUpInside)
  
              overlay.addSubview(favBtn)
              overlay.addSubview(completedBtn)
              overlay.addSubview(homeBtn)
              self.sfController!.view.addSubview(overlay)
  
  
          })
  </code></pre>
  
  <p>Any help will be much appreciated as i am stuck in this issue from long time and cant fine solution. Thanks!</p>