Stabilise MIME types that can be passed to MediaItem.Builder

This is basically 'container' and 'subtitle' MIME types

I previously avoided stabilising any 'custom' MIME types (those
containing '/x-') but it certainly seems reasonable to expect
developers to use APPLICATION_M3U8 and so then it also makes sense
to stabilise other 'similar' custom MIME types too.

PiperOrigin-RevId: 438501642

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

@@ -108,11 +108,10 @@ public final class MimeTypes {
   public static final String APPLICATION_MP4 = BASE_TYPE_APPLICATION + "/mp4";
   public static final String APPLICATION_MP4 = BASE_TYPE_APPLICATION + "/mp4";
   public static final String APPLICATION_WEBM = BASE_TYPE_APPLICATION + "/webm";
   public static final String APPLICATION_WEBM = BASE_TYPE_APPLICATION + "/webm";
 
 
-  @UnstableApi
   public static final String APPLICATION_MATROSKA = BASE_TYPE_APPLICATION + "/x-matroska";
   public static final String APPLICATION_MATROSKA = BASE_TYPE_APPLICATION + "/x-matroska";
 
 
   public static final String APPLICATION_MPD = BASE_TYPE_APPLICATION + "/dash+xml";
   public static final String APPLICATION_MPD = BASE_TYPE_APPLICATION + "/dash+xml";
-  @UnstableApi public static final String APPLICATION_M3U8 = BASE_TYPE_APPLICATION + "/x-mpegURL";
+  public static final String APPLICATION_M3U8 = BASE_TYPE_APPLICATION + "/x-mpegURL";
   public static final String APPLICATION_SS = BASE_TYPE_APPLICATION + "/vnd.ms-sstr+xml";
   public static final String APPLICATION_SS = BASE_TYPE_APPLICATION + "/vnd.ms-sstr+xml";
   public static final String APPLICATION_ID3 = BASE_TYPE_APPLICATION + "/id3";
   public static final String APPLICATION_ID3 = BASE_TYPE_APPLICATION + "/id3";
   public static final String APPLICATION_CEA608 = BASE_TYPE_APPLICATION + "/cea-608";
   public static final String APPLICATION_CEA608 = BASE_TYPE_APPLICATION + "/cea-608";
@@ -135,7 +134,7 @@ public final class MimeTypes {
   @UnstableApi public static final String APPLICATION_EXIF = BASE_TYPE_APPLICATION + "/x-exif";
   @UnstableApi public static final String APPLICATION_EXIF = BASE_TYPE_APPLICATION + "/x-exif";
   @UnstableApi public static final String APPLICATION_ICY = BASE_TYPE_APPLICATION + "/x-icy";
   @UnstableApi public static final String APPLICATION_ICY = BASE_TYPE_APPLICATION + "/x-icy";
   public static final String APPLICATION_AIT = BASE_TYPE_APPLICATION + "/vnd.dvb.ait";
   public static final String APPLICATION_AIT = BASE_TYPE_APPLICATION + "/vnd.dvb.ait";
-  @UnstableApi public static final String APPLICATION_RTSP = BASE_TYPE_APPLICATION + "/x-rtsp";
+  public static final String APPLICATION_RTSP = BASE_TYPE_APPLICATION + "/x-rtsp";
 
 
   // image/ MIME types
   // image/ MIME types