Clean up `Notifier.on_new_room_event` code path (#8288)

The idea here is that we pass the `max_stream_id` to everything, and only use the stream ID of the particular event to figure out *when* the max stream position has caught up to the event and we can notify people about it.

This is to maintain the distinction between the position of an item in the stream (i.e. event A has stream ID 513) and a token that can be used to partition the stream (i.e. give me all events after stream ID 352). This distinction becomes important when the tokens are more complicated than a single number, which they will be once we start tracking the position of multiple writers in the tokens.

The valid operations here are:

1. Is a position before or after a token
2. Fetching all events between two tokens
3. Merging multiple tokens to get the "max", i.e. `C = max(A, B)` means that for all positions P where P is before A *or* before B, then P is before C.

Future PR will change the token type to a dedicated type.

1 files changed, 0 insertions, 4 deletions

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index d1556659e3..276de8f8d0 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -387,8 +387,6 @@ class EventCreationHandler:
         # This is only used to get at ratelimit function, and maybe_kick_guest_users
         self.base_handler = BaseHandler(hs)
 
-        self.pusher_pool = hs.get_pusherpool()
-
         # We arbitrarily limit concurrent event creation for a room to 5.
         # This is to stop us from diverging history *too* much.
         self.limiter = Linearizer(max_count=5, name="room_event_creation_limit")
@@ -1145,8 +1143,6 @@ class EventCreationHandler:
             # If there's an expiry timestamp on the event, schedule its expiry.
             self._message_handler.maybe_schedule_expiry(event)
 
-        await self.pusher_pool.on_new_notifications(max_stream_id)
-
         def _notify():
             try:
                 self.notifier.on_new_room_event(