title: ClipsToBounds is not working in cells
body: <p>I have an UITableView with custom cells. The structure of every cell is like that: I have contentView, in this contentView I have backView (simple UIView with white background and cornered radius 16.0), in this backView I have an imageView with some picture.</p>
  
  <p>What I want is to have this imageView cornered (within his parent UIView — backView — borders). And it doesn't work this way.</p>
  
  <p>The code is quite simple (from ImageCell.swift):</p>
  
  <pre><code>    self.backView = UIView()
      self.backView.backgroundColor = UIColor.white
      self.backView.translatesAutoresizingMaskIntoConstraints = false
      self.backView.layer.cornerRadius = 16.0
      self.contentView.addSubview(backView)
  
      self.picture = UIImageView()
      self.picture.translatesAutoresizingMaskIntoConstraints = false
      self.picture.contentMode = UIViewContentMode.scaleAspectFill
      self.picture.backgroundColor = UIColor.gray
      self.picture.clipsToBounds = true
      self.backView.addSubview(picture)
  
      let constraintPicTop = NSLayoutConstraint(item: picture, attribute: .top, relatedBy: .equal, toItem: contentView, attribute: .topMargin, multiplier: 1.0, constant: -6)
      let constraintPicLeft = NSLayoutConstraint(item: picture, attribute: .left, relatedBy: .equal, toItem: backView, attribute: .leftMargin, multiplier: 1.0, constant: -8)
      let constraintPicRight = NSLayoutConstraint(item: picture, attribute: .right, relatedBy: .equal, toItem: backView, attribute: .rightMargin, multiplier: 1.0, constant: 8)
      constraintBottomPic = NSLayoutConstraint(item: picture, attribute: .bottom, relatedBy: .lessThanOrEqual, toItem: contentView, attribute: .topMargin, multiplier: 1.0, constant: 150)
  </code></pre>
  
  <p>I don't know the size of the image beforehand, so constraintBottomPic value is updating in cellForRowAt function.</p>
  
  <p>And it's working except this image is not cornered (and I believe it should be).</p>
  
  <p>(It's not possible for me to set cornerRadius for UIImageView unfortunately).</p>
  
  <p><strong>update:</strong> Found the solution. It seems I had to set 'clipsToBounds' to true in all the parent views directly (contentView and backView, in my case).</p>