Augment scene and navigation bar methods

ExNavigator.js

@@ -46,10 +46,6 @@ export default class ExNavigator extends React.Component {
     });
   }
 
-  get navigationContext() {
-    return this._navigator ? this._navigator.navigationContext : null;
-  }
-
   render() {
     return (
       <Navigator
@@ -70,10 +66,11 @@ export default class ExNavigator extends React.Component {
     // mounted because it emits a didfocus event when it is mounted, before we
     // can get a ref to it
     if (!this._subscribedToFocusEvents) {
-      this._subscribeToFocusEvents(this);
+      this._subscribeToFocusEvents(navigator);
     }
 
     let scene = this._routeRenderer.renderScene(route, this);
+    scene = this.augmentScene(scene, route);
     let firstRoute = navigator.getCurrentRoutes()[0];
     if (route === firstRoute) {
       scene = cloneReferencedElement(scene, {
@@ -88,12 +85,14 @@ export default class ExNavigator extends React.Component {
       return null;
     }
 
-    return (
+    let navigationBar = (
       <Navigator.NavigationBar
         routeMapper={this._routeRenderer.navigationBarRouteMapper}
         style={[ExNavigatorStyles.bar, this.props.navigationBarStyle]}
       />
     );
+
+    return this.augmentNavigationBar(navigationBar);
   }
 
   @autobind
@@ -186,6 +185,16 @@ export default class ExNavigator extends React.Component {
   popToTop() {
     return this._navigator.popToTop();
   }
+
+  // Methods to override
+
+  augmentScene(scene, route: ExRoute) {
+    // Override
+  }
+
+  augmentNavigationBar(navigationBar: Navigator.NavigationBar) {
+    // Override
+  }
 }
 
 export * from './ExRoute';