Un-hide some of the APIs in relation to nav state API.

Also removed some now-redundant methods. Since these methods were
previously @hide, there should be no harm in removing them as we
un-@hide onEvent.

Test: make update-car-api
Change-Id: I28d4621b3bcae01489dceea487d15878bbbeaa6b
diff --git a/car-lib/api/system-current.txt b/car-lib/api/system-current.txt
index 390e1fc..a4856cd 100644
--- a/car-lib/api/system-current.txt
+++ b/car-lib/api/system-current.txt
@@ -137,10 +137,7 @@
   public abstract class NavigationRenderer {
     ctor public NavigationRenderer();
     method public abstract android.car.navigation.CarNavigationInstrumentCluster getNavigationProperties();
-    method public abstract void onNextTurnChanged(int, java.lang.CharSequence, int, int, android.graphics.Bitmap, int);
-    method public abstract void onNextTurnDistanceChanged(int, int, int, int);
-    method public abstract void onStartNavigation();
-    method public abstract void onStopNavigation();
+    method public abstract void onEvent(int, android.os.Bundle);
   }
 
 }