title: UIView is not updating when popToViewController on NavigationController
body: <p>I have a navigationController where I <code>pushViewController</code> two viewcontrollers, <code>OneViewController</code> and <code>TwoViewController</code>. When I rotating the device on the pushed <code>TwoViewController</code>, and then <code>popToViewController</code> (see code) back to <code>OneViewController</code> the view on <code>OneViewController</code> is not updated / rotated. </p>
  
  <p>Update: I have created a small sample project, where I have added a navigationController and two ViewControllers - and then doing the same thing. That is actually working, the only different I can think of is that the Views in my application that fails, is that I load the views from Xib files.</p>
  
  <p>All the constraints in the view is setup in Interface Builder - and saved to the xib file.</p>
  
  <p>I have the following in the view that I reference in Interface Builder as the ViewControllers view:</p>
  
  <pre><code>func loadViewFromNib() -&gt; UIView? {
      let bundle = Bundle(for: type(of: self))
      let nib = UINib(nibName: String(describing: type(of: self)), bundle: bundle)
      return nib.instantiate(
          withOwner: self,
          options: nil).first as? UIView
  }
  
  override public func awakeFromNib() {
   super.awakeFromNib()
   // Not setting up any constraints in code of setting any frame here.
  }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/arX72.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/arX72.png" alt="enter image description here"></a></p>
  
  <p>If I then rotate on the <code>OneViewController</code> it then renders fine.</p>
  
  <p>Do you know why it is not updating when using popToViewController?</p>
  
  <pre><code>        let viewControllers: [UIViewController] = self.navigationController!.viewControllers
          for aViewController in viewControllers {
              if aViewController is OneViewController {
  
                      aViewController.view.updateConstraints()
                      aViewController.view.setNeedsDisplay()
                      aViewController.view.layoutIfNeeded()
                      aViewController.view.setNeedsLayout()
  
                  self.navigationController!.popToViewController(aViewController, animated: true)
                  break
              }
          }
  </code></pre>
  
  <p>On the view I have also tried this:</p>
  
  <pre><code>override func viewWillShow(passingInAnyObject: AnyObject?) {
      self.updateConstraints()
      self.setNeedsDisplay()
      self.layoutIfNeeded()
      self.setNeedsLayout()
  }
  </code></pre>