title: How to resize UINavigationController's view controllers frame after it is resized
body: <p>I have a UINavigationController that is added as a child view controller to a container UIViewController class. I need to dynamically display a banner view above the navigation controller's view. I resize the navigation controller's view but I'm unable to resize the navigation controller's child view controller's views.</p>
  
  <p>// this code updates the navigation controller's view, but it does not update the height of its child view controller's view. </p>
  
  <pre><code>self.updateViewYOffset(self.rootNavigationController.view, yOffset: yOffset)
  
  func updateViewYOffset(view: UIView, yOffset: CGFloat) {
      var frame = view.frame
      frame.origin.y = yOffset
      frame.size.height = self.view.frame.size.height - yOffset
      view.frame = frame
  }
  </code></pre>
  
  <p>// if iPhone 5s - the navigation controller's view height is now 538 (568-30) but its child view controller's views height is still 568.</p>