[extractors] Use new framework for existing embeds (#4307)

`Brightcove` is difficult to migrate because it's subclasses may depend
on the signature of the current functions. So it is left as-is for now

Note: Tests have not been migrated

yt_dlp/extractor/vzaar.py

@@ -1,5 +1,3 @@
-import re
-
 from .common import InfoExtractor
 from ..compat import compat_str
 from ..utils import (
@@ -12,6 +10,7 @@ from ..utils import (
 
 class VzaarIE(InfoExtractor):
     _VALID_URL = r'https?://(?:(?:www|view)\.)?vzaar\.com/(?:videos/)?(?P<id>\d+)'
+    _EMBED_REGEX = [r'<iframe[^>]+src=["\'](?P<url>(?:https?:)?//(?:view\.vzaar\.com)/[0-9]+)']
     _TESTS = [{
         # HTTP and HLS
         'url': 'https://vzaar.com/videos/1152805',
@@ -47,12 +46,6 @@ class VzaarIE(InfoExtractor):
         'only_matching': True,
     }]
 
-    @staticmethod
-    def _extract_urls(webpage):
-        return re.findall(
-            r'<iframe[^>]+src=["\']((?:https?:)?//(?:view\.vzaar\.com)/[0-9]+)',
-            webpage)
-
     def _real_extract(self, url):
         video_id = self._match_id(url)
         video_data = self._download_json(