Transform double-tap of HEADSETHOOK to skip-to-next

As reported in Issue: #1493 we already use `HEADSETHOOK` to start
waiting for a double-tap, but we don't consider it for the second tap.

Similarly, we previously considered `PLAY` for the second tap, but not the first.
Only `HEADSETHOOK` and `PLAY_PAUSE` are
[documented](https://developer.android.com/reference/androidx/media3/session/MediaSession#media-key-events-mapping)
to transform double-tap to `seekToNext`. So this change removes the
`PLAY` detection from the second tap.

#cherrypick

PiperOrigin-RevId: 651017522

RELEASENOTES.md

@@ -64,6 +64,10 @@
         playback can't be suppressed without the system crashing the service
         with a `ForegroundServiceDidNotStartInTimeException`
         ([#1528](https://github.com/google/ExoPlayer/issues/1528)).
+    *   Transform a double-tap of `KEYCODE_HEADSETHOOK` into a 'seek to next'
+        action, as
+        [documented](https://developer.android.com/reference/androidx/media3/session/MediaSession#media-key-events-mapping)
+        ([#1493](https://github.com/androidx/media/issues/1493)).
 *   UI:
 *   Downloads:
 *   OkHttp Extension:

libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java

@@ -1242,7 +1242,8 @@ private void handleAvailablePlayerCommandsChanged(Player.Commands availableComma
     }
 
     if (!isMediaNotificationControllerConnected()) {
-      if (keyCode == KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE && doubleTapCompleted) {
+      if ((keyCode == KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE || keyCode == KeyEvent.KEYCODE_HEADSETHOOK)
+          && doubleTapCompleted) {
         // Double tap completion for legacy when media notification controller is disabled.
         sessionLegacyStub.onSkipToNext();
         return true;
@@ -1262,7 +1263,7 @@ private boolean applyMediaButtonKeyEvent(KeyEvent keyEvent, boolean doubleTapCom
     ControllerInfo controllerInfo = checkNotNull(instance.getMediaNotificationControllerInfo());
     Runnable command;
     int keyCode = keyEvent.getKeyCode();
-    if ((keyCode == KEYCODE_MEDIA_PLAY_PAUSE || keyCode == KEYCODE_MEDIA_PLAY)
+    if ((keyCode == KEYCODE_MEDIA_PLAY_PAUSE || keyCode == KeyEvent.KEYCODE_HEADSETHOOK)
         && doubleTapCompleted) {
       keyCode = KEYCODE_MEDIA_NEXT;
     }

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaSessionKeyEventTest.java

@@ -346,6 +346,20 @@ public void playPauseKeyEvent_doubleTapOnPlayPause_seekNext() throws Exception {
     player.awaitMethodCalled(MockPlayer.METHOD_SEEK_TO_NEXT, TIMEOUT_MS);
   }
 
+  @Test
+  public void playPauseKeyEvent_doubleTapOnHeadsetHook_seekNext() throws Exception {
+    Assume.assumeTrue(Util.SDK_INT >= 21); // TODO: b/199064299 - Lower minSdk to 19.
+    handler.postAndSync(
+        () -> {
+          player.playWhenReady = true;
+          player.playbackState = Player.STATE_READY;
+        });
+
+    dispatchMediaKeyEvent(KeyEvent.KEYCODE_HEADSETHOOK, /* doubleTap= */ true);
+
+    player.awaitMethodCalled(MockPlayer.METHOD_SEEK_TO_NEXT, TIMEOUT_MS);
+  }
+
   private MediaController connectMediaNotificationController() throws Exception {
     return threadTestRule
         .getHandler()