fix(demo): make DraggableMarkerDemo extend AbstractGoogleMapsDemo

Author: paodb

src/test/java/com/flowingcode/vaadin/addons/googlemaps/DraggableMarkerDemo.java

@@ -2,36 +2,27 @@
 
 import com.flowingcode.vaadin.addons.demo.DemoSource;
 import com.flowingcode.vaadin.addons.googlemaps.GoogleMap.MapType;
-import com.vaadin.flow.component.html.H2;
 import com.vaadin.flow.component.notification.Notification;
-import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 import com.vaadin.flow.router.PageTitle;
 
 @PageTitle("Draggable Marker Demo")
 @DemoSource(
     "https://github.com/FlowingCode/GoogleMapsAddon/blob/master/src/test/java/com/flowingcode/vaadin/addons/googlemaps/DraggableMarkerDemo.java")
 @SuppressWarnings("serial")
-public class DraggableMarkerDemo extends VerticalLayout {
-  
-  public DraggableMarkerDemo() {
-    this.setSizeFull();
-    String apiKey = System.getProperty("google.maps.api");
-    if (apiKey == null) {
-      add(
-          new H2(
-              "Api key is needded to run the demo, pass it using the following system property: '-Dgoogle.maps.api=<your-api-key>'"));
-    } else {
-      GoogleMap gmaps = new GoogleMap(apiKey, null, null);
-      gmaps.setMapType(MapType.ROADMAP);
-      gmaps.setSizeFull();
-      gmaps.setCenter(new LatLon(-31.636036, -60.7055271));
-      
-      gmaps.addMarker("Center", gmaps.getCenter(), true, Markers.PURPLE)
-      .addDragEndEventListener(
-          e -> 
-            Notification.show("Lat: " + e.getLatitude() + " - Lng: " + e.getLongitude()));
-                       
-      add(gmaps);
-    }
+public class DraggableMarkerDemo extends AbstractGoogleMapsDemo {
+ 
+  @Override
+  protected void createGoogleMapsDemo(String apiKey) {
+    GoogleMap gmaps = new GoogleMap(apiKey, null, null);
+    gmaps.setMapType(MapType.ROADMAP);
+    gmaps.setSizeFull();
+    gmaps.setCenter(new LatLon(-31.636036, -60.7055271));
+    
+    gmaps.addMarker("Center", gmaps.getCenter(), true, Markers.PURPLE)
+    .addDragEndEventListener(
+        e -> 
+          Notification.show("Lat: " + e.getLatitude() + " - Lng: " + e.getLongitude()));
+                     
+    add(gmaps);    
   }
 }