Remove the deprecated BaseHandler. (#11005)

The shared ratelimit function was replaced with a dedicated
RequestRatelimiter class (accessible from the HomeServer
object).

Other properties were copied to each sub-class that inherited
from BaseHandler.

synapse/handlers/room.py

@@ -76,8 +76,6 @@ from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.stringutils import parse_and_validate_server_name
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -88,15 +86,18 @@ id_server_scheme = "https://"
 FIVE_MINUTES_IN_MS = 5 * 60 * 1000
 
 
-class RoomCreationHandler(BaseHandler):
+class RoomCreationHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.clock = hs.get_clock()
+        self.hs = hs
         self.spam_checker = hs.get_spam_checker()
         self.event_creation_handler = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
         self._event_auth_handler = hs.get_event_auth_handler()
         self.config = hs.config
+        self.request_ratelimiter = hs.get_request_ratelimiter()
 
         # Room state based off defined presets
         self._presets_dict: Dict[str, Dict[str, Any]] = {
@@ -162,7 +163,7 @@ class RoomCreationHandler(BaseHandler):
         Raises:
             ShadowBanError if the requester is shadow-banned.
         """
-        await self.ratelimit(requester)
+        await self.request_ratelimiter.ratelimit(requester)
 
         user_id = requester.user.to_string()
 
@@ -665,7 +666,7 @@ class RoomCreationHandler(BaseHandler):
             raise SynapseError(403, "You are not permitted to create rooms")
 
         if ratelimit:
-            await self.ratelimit(requester)
+            await self.request_ratelimiter.ratelimit(requester)
 
         room_version_id = config.get(
             "room_version", self.config.server.default_room_version.identifier