ShowRandomColor. Add support for the user tapping a shortcut

AppDelegate.swift

//
//  AppDelegate.swift
//  ShowRandomColor
//
//  Created by Russell Archer on 05/10/2018.
//  Copyright © 2018 Russell Archer. All rights reserved.
//

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication,
                     continue userActivity: NSUserActivity,
                     restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
        
        if userActivity.interaction?.intent is ShowRandomColorIntent {
            let viewController = window?.rootViewController as! ViewController
            viewController.setColor()
            return true
        }
        
        return false
    }
  
    // Other methods not shown for brevity
}