title: layer.cornerRadius not working in conjunction with NSLayoutConstraints (swift 3)
body: <p>Below are my profile view constraints and the view renders well, however the width consistently returns zero. So that final constraint, profileImageView.layer.cornerRadius = (profile.frame.width / 2) returns zero everytime.</p>
  
  <pre><code>    profileImageView.translatesAutoresizingMaskIntoConstraints = false
  
  
      addConstraint(NSLayoutConstraint(item: profileImageView, attribute: .width, relatedBy: .equal, toItem: containerView, attribute: .width, multiplier: 0.125, constant: 0))
  
  
      addConstraint(NSLayoutConstraint(item: profileImageView, attribute: .height, relatedBy: .equal, toItem: containerView, attribute: .width, multiplier: 0.125, constant: 0))
  
  
  
  
      addConstraint(NSLayoutConstraint(item: profileImageView, attribute: .centerY, relatedBy: .equal, toItem: containerView, attribute: .centerY, multiplier: 1, constant: 0))
  
      addConstraint(NSLayoutConstraint(item: profileImageView, attribute: .centerX, relatedBy: .equal, toItem: containerView, attribute: .centerX, multiplier: 0.25, constant: 0))
  
      profileImageView.layer.cornerRadius = (profileImageView.frame.width / 2)
  </code></pre>
  
  <p>Any suggestions?</p>
  
  <p><a href="https://i.stack.imgur.com/dTNWf.png" rel="noreferrer"><img src="https://i.stack.imgur.com/dTNWf.png" alt="enter image description here"></a></p>