Make setFullscreenButtonState UnstableApi

RELEASENOTES.md

@@ -50,10 +50,9 @@
         [#1594](https://github.com/androidx/media/issues/1594)).
     *   Add `setFullscreenButtonState` to `PlayerView` to allow updates of
         fullscreen button's icon on demand, i.e. out-of-band and not reactively
-        to a click interaction.
+        to a click interaction
         ([#1590](https://github.com/androidx/media/issues/1590),
-        [#184](https://github.com/androidx/media/issues/184),
-        [#10391](https://github.com/google/ExoPlayer/issues/10391))
+        [#184](https://github.com/androidx/media/issues/184)).
 *   Downloads:
 *   OkHttp Extension:
 *   Cronet Extension:

libraries/ui/src/main/java/androidx/media3/ui/PlayerControlView.java

@@ -1582,16 +1582,14 @@ private void onFullScreenButtonClicked(View v) {
    * Updates whether the controller is in fullscreen, changing its fullscreen icon and reports it to
    * to the listener.
    *
-   * <p>For {@code isFullscreen} equals {@code true} the icon will be set to {@link
-   * R.drawable#exo_styled_controls_fullscreen_exit} or else {@link
-   * R.drawable#exo_styled_controls_fullscreen_enter}.
+   * <p>For {@code isFullscreen} equals {@code true} the icon will be set to
+   * {@code @drawable/exo_styled_controls_fullscreen_exit} or else
+   * {@code @drawable/exo_styled_controls_fullscreen_enter}.
    *
    * @param isFullscreen If the view is in full screen.
    */
   public void updateIsFullscreen(boolean isFullscreen) {
-    boolean fullscreenModeChanged = this.isFullScreen != isFullscreen;
-
-    if (!fullscreenModeChanged) {
+    if (this.isFullScreen == isFullscreen) {
       return;
     }
 

libraries/ui/src/main/java/androidx/media3/ui/PlayerView.java

@@ -1148,6 +1148,7 @@ public void setFullscreenButtonClickListener(@Nullable FullscreenButtonClickList
    *
    * @param isFullscreen Whether the player is currently in fullscreen.
    */
+  @UnstableApi
   public void setFullscreenButtonState(boolean isFullscreen) {
     Assertions.checkStateNotNull(controller);
     controller.updateIsFullscreen(isFullscreen);