[YouTube] Extract xtags of formats

Extracts the `xtags` field, which encodes additional data of the format, such
as if the format is using dynamic range compression.
This is required for using SABR.

Author: FineFindus

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java

@@ -268,6 +268,7 @@ public MediaFormat getMediaFormat() {
     private Locale audioLocale;
 
     private long lastModified;
+    private String xtags;
     private boolean isDrc;
 
     public long getLastModified() {
@@ -278,6 +279,14 @@ public void setLastModified(final long lastModified) {
         this.lastModified = lastModified;
     }
 
+    public String getXtags() {
+        return xtags;
+    }
+
+    public void setXtags(final String xtags) {
+        this.xtags = xtags;
+    }
+
     public Boolean isDrc() {
         return isDrc;
     }

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamExtractor.java

@@ -1423,6 +1423,7 @@ private ItagInfo buildAndAddItagInfoToList(
         itagItem.setCodec(codec);
         itagItem.setIsDrc(formatData.getBoolean("isDrc", false));
         itagItem.setLastModified(Long.parseLong(formatData.getString("lastModified", "-1")));
+        itagItem.setXtags(formatData.getString("xtags"));
 
         if (streamType == StreamType.LIVE_STREAM || streamType == StreamType.POST_LIVE_STREAM) {
             itagItem.setTargetDurationSec(formatData.getInt("targetDurationSec"));