anchor.diff:    // update the references to the activeRoute and previousRoute. if you switch between routes quickly you may go to a
     // new route before the previous route's transition animation has completed. if that's the case we need to remove
     // the previous route's content before we replace the reference to the previous route.
  -  if (router.previousRoute != null &&
  -      router.previousRoute.transitionAnimationInProgress) {
  -    transitionAnimationEnd(router.previousRoute);
  -  }
  -  if (router.activeRoute != null) {
  -    router.activeRoute.active = false;
  -  }
  -  router.previousRoute = router.activeRoute;
  -  router.activeRoute = route;
  -  router.activeRoute.active = true;
  +  if (router._previousRoute != null &&
  +      router._previousRoute.transitionAnimationInProgress) {
  +    transitionAnimationEnd(router._previousRoute);
  +  }
  +  if (router._activeRoute != null) {
  +    router._activeRoute.active = false;
  +  }
  +  router._previousRoute = router._activeRoute;
  +  router._activeRoute = route;
  +  router._activeRoute.active = true;
   
     // import custom element or template
     if (route.imp != null) {
  
positive.code: 
    /// Initialize the router: core-animated-pages and listen for change events.
    void initialize() {
      if (isInitialized) {
        return;
      }
      isInitialized = true;
  
      // <app-router core-animated-pages transitions="hero-transition cross-fade">
      if (core_animated_pages) {
  
negative.code:   @published bool bindRouter;
  
    /// Is the router initilized already?
    bool _isInitialized = false;
    /// Previous active route.
    WebRoute _previousRoute;
    /// Previous active URL.
    RouteUri _previousUrl;
    /// Currently active route.
    WebRoute _activeRoute;
    /// CoreAnimatedPages element.
    CoreAnimatedPages _coreAnimatedPages;
    /// CoreAjax element for on-demand retrieving of route's elements.
    CoreAjax _ajax;
    /// Subscription of popstate events (for address change monitoring).
    StreamSubscription<PopStateEvent> _popStateSubscription;
  
    @override
    WebRouter.created() : super.created();
  