Link MediaRouter2 from MediaRouter

Recommend using MediaRouter2 over MediaRouter

Bug: 148379928
Test: N/A
Change-Id: I0fea9f46f6956a42399b9c9b742438168e7b20a7

media/java/android/media/MediaRouter.java

@@ -64,7 +64,12 @@ import java.util.concurrent.CopyOnWriteArrayList;
  *
  * <p>The media router API is not thread-safe; all interactions with it must be
  * done from the main thread of the process.</p>
+ *
+ * <p>
+ * We recommend using {@link android.media.MediaRouter2} APIs for new applications.
+ * </p>
  */
+//TODO: Link androidx.media2.MediaRouter when we are ready.
 @SystemService(Context.MEDIA_ROUTER_SERVICE)
 public class MediaRouter {
     private static final String TAG = "MediaRouter";