title: Cancel button is not shown in UISearchBar
body: <p>I have <code>UICollectionView</code>. On clicking search button in <code>UINavigationBar</code>, I am adding the <code>UISearchController</code>'s <code>searchbar</code> as titleview for <code>UINavigationItem</code>. For iPhone it is working properly. For iPad the <code>cancel</code> button is not shown. The Searchbar alone takes the entire width.</p>
  
  <p><img src="https://i.stack.imgur.com/ujsd7.png" alt="enter image description here"></p>
  
  <p>Can anyone help me out on this?. Thanks in advance.</p>