[common] Make mark_watched() more lenient

youtube_dl/extractor/common.py

@@ -3001,7 +3001,11 @@ class InfoExtractor(object):
         if (self._downloader.params.get('mark_watched', False)
                 and (self._get_login_info()[0] is not None
                      or self._downloader.params.get('cookiefile') is not None)):
-            self._mark_watched(*args, **kwargs)
+            # extractors apart from YoutubeIE can mark: be more lenient
+            try:
+                self._mark_watched(*args, **kwargs)
+            except NotImplementedError:
+                self.report_warning('Marking as watched is not supported')
 
     def _mark_watched(self, *args, **kwargs):
         raise NotImplementedError('This method must be implemented by subclasses')