ViewProtocol.swift

import UIKit

protocol ViewProtocol { 
    var view: UIView { get }
}

extension ViewProtocol where Self: UIView {
    var view: UIView {
        return self
    }
}

extension ViewProtocol {
    var backgroundColor: UIColor? {
        get {
            return view.backgroundColor
        }
        set {
            view.backgroundColor = newValue
        }
    }
}