CameraPreviewView.swift

import UIKit
import AVFoundation

class CameraPreviewView: UIView {

    override class func layerClass() -> AnyClass {
        return AVCaptureVideoPreviewLayer.self
    }
    
    var session: AVCaptureSession! {
        get {
            let layer = self.layer as? AVCaptureVideoPreviewLayer
            return layer?.session
        }
        set {
            if let layer = self.layer as? AVCaptureVideoPreviewLayer {
                layer.session = newValue
            }
        }
    }
    
}