title: Draw polyline using Google Maps in custom view with Swift 3
body: <p>I am trying to draw route between two places using Google Maps on a custom UIView but not able to get it correctly implemented. My custom view is mapViewX. I've installed google sdk using pods which includes pod 'GoogleMaps' and pod 'GooglePlaces'. I made custom-view Class as 'GMSMapView'. my code is : </p>
  
  <pre><code>    @IBOutlet weak var mapViewX: GMSMapView!
  
  override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.
  
      let path = GMSMutablePath()
      path.add(CLLocationCoordinate2D(latitude: 37.778483, longitude: -122.513960))
      path.add(CLLocationCoordinate2D(latitude: 37.706753, longitude: -122.418677))
      let polyline = GMSPolyline(path: path)
      polyline.strokeColor = .black
      polyline.strokeWidth = 10.0
      polyline.map = mapViewX
  
  }
  </code></pre>
  
  <p>Please help!</p>