title: webView height constraint based on dynamic content
body: <p>I have an embedded webView at the bottom of a screen, which loads the Facebook comments javascript plugin.</p>
  
  <p>I want this webView to be seamlessly integrated in the screen, without forcing the user to scroll its contents.</p>
  
  <p>However, when the user taps on some of the webView buttons, the UI height changes, making the webView scrollable.</p>
  
  <h2>Question</h2>
  
  <p>How do I dynamically update the webView height constraint based on its dynamic contents?</p>