web_view_wrapper.swift

class LegacyWebView: UIView, URLRequestable {
  
  private var webView: UIWebView!
  
  func load(urlRequest: URLRequest) {
    webView.loadRequest(urlRequest)
  }
  
  // other code here
  
}

class ModernWebView: UIView, URLRequestable {
  
  private var webView: WKWebView!
  
  func load(urlRequest: URLRequest) {
    webView.load(urlRequest)
  }
  
  // other code here
  
}