Add missing @Nullable to method override.

Method override parameter nullness should contravariant.

PiperOrigin-RevId: 358772798

library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -2072,7 +2072,7 @@ public class SimpleExoPlayer extends BasePlayer
     }
     }
 
 
     @Override
     @Override
-    public void onRenderedFirstFrame(Surface surface) {
+    public void onRenderedFirstFrame(@Nullable Surface surface) {
       analyticsCollector.onRenderedFirstFrame(surface);
       analyticsCollector.onRenderedFirstFrame(surface);
       if (SimpleExoPlayer.this.surface == surface) {
       if (SimpleExoPlayer.this.surface == surface) {
         for (VideoListener videoListener : videoListeners) {
         for (VideoListener videoListener : videoListeners) {