class LayoutTestVC: UIViewController {
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		let testView = YourCustomView(frame: .init(x: 0, y: 0, width: 300, height: 160))
	}
	
}

class ContentView: UIView {
}

class YourCustomView: UIView {
	
	var contentView: ContentView!
	let thumbWidth: CGFloat = 40.0
	
	override init(frame: CGRect) {
		super.init(frame: frame)
		setupContentView()
	}
	required init?(coder: NSCoder) {
		super.init(coder: coder)
		setupContentView()
	}
	
	private func setupContentView() {
		contentView = ContentView(frame: .zero)
		contentView.translatesAutoresizingMaskIntoConstraints = false
		addSubview(contentView)
		contentView.leftAnchor.constraint(equalTo: leftAnchor, constant:thumbWidth).isActive = true
		contentView.rightAnchor.constraint(equalTo: rightAnchor, constant: -thumbWidth).isActive = true
		contentView.topAnchor.constraint(equalTo: topAnchor).isActive = true
		contentView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
		contentView.clipsToBounds = true
		contentView.isUserInteractionEnabled = true
		contentView.layoutIfNeeded()
		NSLog("ContentView bounds \(contentView.bounds), view bounds \(self.bounds)")
	}
	
}