Make SimpleBasePlayer.State public

This ensures it's easier to handle these State updates in other
helper classes if needed.

Issue: androidx/media#2128

#cherrypick

PiperOrigin-RevId: 728264396

RELEASENOTES.md

@@ -3,6 +3,9 @@
 ### Unreleased changes
 
 *   Common Library:
+    *   Change `SimpleBasePlayer.State` access from protected to public to make
+        it easier to handle updates in other classes
+        ([#2128](https://github.com/androidx/media/issues/2128)).
 *   ExoPlayer:
 *   Transformer:
 *   Track Selection:

libraries/common/src/main/java/androidx/media3/common/SimpleBasePlayer.java

@@ -96,7 +96,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 public abstract class SimpleBasePlayer extends BasePlayer {
 
   /** An immutable state description of the player. */
-  protected static final class State {
+  public static final class State {
 
     /** A builder for {@link State} objects. */
     public static final class Builder {