Fix recursive loop when registering controller visibility listeners

There are two overloads of this method due to a type 'rename' from
`PlayerControlView.VisibilityListener` to
`PlayerView.ControllerVisibilityListener`. Currently when you call one
overload it passes `null` to the other one (to clear the other listener).
Unfortunately this results in it clearing itself, because it receives
a null call back!

This change tweaks the documentation to clarify that the 'other'
listener is only cleared if you pass a non-null listener in. This solves
the recursive problem, and allows the 'legacy' visibility listener to be
successfully registered.

Issue: androidx/media#229

#minor-release

PiperOrigin-RevId: 496876397
(cherry picked from commit 37fd65a)

library/ui/src/main/java/com/google/android/exoplayer2/ui/StyledPlayerView.java

@@ -868,23 +868,25 @@ public void setControllerHideDuringAds(boolean controllerHideDuringAds) {
   /**
    * Sets the {@link StyledPlayerControlView.VisibilityListener}.
    *
-   * <p>Removes any listener set by {@link
-   * #setControllerVisibilityListener(StyledPlayerControlView.VisibilityListener)}.
+   * <p>If {@code listener} is non-null then any listener set by {@link
+   * #setControllerVisibilityListener(StyledPlayerControlView.VisibilityListener)} is removed.
    *
    * @param listener The listener to be notified about visibility changes, or null to remove the
    *     current listener.
    */
   @SuppressWarnings("deprecation") // Clearing the legacy listener.
   public void setControllerVisibilityListener(@Nullable ControllerVisibilityListener listener) {
     this.controllerVisibilityListener = listener;
-    setControllerVisibilityListener((StyledPlayerControlView.VisibilityListener) null);
+    if (listener != null) {
+      setControllerVisibilityListener((StyledPlayerControlView.VisibilityListener) null);
+    }
   }
 
   /**
    * Sets the {@link StyledPlayerControlView.VisibilityListener}.
    *
-   * <p>Removes any listener set by {@link
-   * #setControllerVisibilityListener(ControllerVisibilityListener)}.
+   * <p>If {@code listener} is non-null then any listener set by {@link
+   * #setControllerVisibilityListener(ControllerVisibilityListener)} is removed.
    *
    * @deprecated Use {@link #setControllerVisibilityListener(ControllerVisibilityListener)} instead.
    */
@@ -903,8 +905,8 @@ public void setControllerVisibilityListener(
     this.legacyControllerVisibilityListener = listener;
     if (listener != null) {
       controller.addVisibilityListener(listener);
+      setControllerVisibilityListener((ControllerVisibilityListener) null);
     }
-    setControllerVisibilityListener((ControllerVisibilityListener) null);
   }
 
   /**