title: Equivalent PreferredContentSize when using ChildViewControllers
body: <p>Am trying to switch over from using <code>UIPopoverController</code> to <code>ChildViewControllers</code> on iPad. We have 4 or 5 VC's that <code>navigate</code> within the parent nav subview controller, all with different sizes, each time we push or pop, the parent popover resizes based on the <code>PreferredContentSize</code> for the vc. Now have switched over to <code>AddChildViewController</code>, the parent vc keeps same size, is there an equivalent <code>PreferredContentSize</code> for <code>ChildViewControllers</code>?</p>
  
  <p>thanks</p>