Remove necessity to pass ConsensusEngineId when registering notifications protocol (#7549)

* Remove necessity to pass ConsensusEngineId when registering notifications protocol

* Line width

* Fix tests protocol name

* Other renames

* Doc update

* Change issue in TODO

substrate/client/network/src/behaviour.rs

@@ -30,7 +30,7 @@ use libp2p::kad::record;
 use libp2p::swarm::{NetworkBehaviourAction, NetworkBehaviourEventProcess, PollParameters};
 use log::debug;
 use sp_consensus::{BlockOrigin, import_queue::{IncomingBlock, Origin}};
-use sp_runtime::{traits::{Block as BlockT, NumberFor}, ConsensusEngineId, Justification};
+use sp_runtime::{traits::{Block as BlockT, NumberFor}, Justification};
 use std::{
 	borrow::Cow,
 	collections::{HashSet, VecDeque},
@@ -131,7 +131,7 @@ pub enum BehaviourOut<B: BlockT> {
 		/// Node we opened the substream with.
 		remote: PeerId,
 		/// The concerned protocol. Each protocol uses a different substream.
-		engine_id: ConsensusEngineId,
+		protocol: Cow<'static, str>,
 		/// Object that permits sending notifications to the peer.
 		notifications_sink: NotificationsSink,
 		/// Role of the remote.
@@ -147,7 +147,7 @@ pub enum BehaviourOut<B: BlockT> {
 		/// Id of the peer we are connected to.
 		remote: PeerId,
 		/// The concerned protocol. Each protocol uses a different substream.
-		engine_id: ConsensusEngineId,
+		protocol: Cow<'static, str>,
 		/// Replacement for the previous [`NotificationsSink`].
 		notifications_sink: NotificationsSink,
 	},
@@ -158,7 +158,7 @@ pub enum BehaviourOut<B: BlockT> {
 		/// Node we closed the substream with.
 		remote: PeerId,
 		/// The concerned protocol. Each protocol uses a different substream.
-		engine_id: ConsensusEngineId,
+		protocol: Cow<'static, str>,
 	},
 
 	/// Received one or more messages from the given node using the given protocol.
@@ -166,7 +166,7 @@ pub enum BehaviourOut<B: BlockT> {
 		/// Node we received the message from.
 		remote: PeerId,
 		/// Concerned protocol and associated message.
-		messages: Vec<(ConsensusEngineId, Bytes)>,
+		messages: Vec<(Cow<'static, str>, Bytes)>,
 	},
 
 	/// Events generated by a DHT as a response to get_value or put_value requests as well as the
@@ -257,19 +257,20 @@ impl<B: BlockT, H: ExHashT> Behaviour<B, H> {
 	/// will retain the protocols that were registered then, and not any new one.
 	pub fn register_notifications_protocol(
 		&mut self,
-		engine_id: ConsensusEngineId,
-		protocol_name: impl Into<Cow<'static, str>>,
+		protocol: impl Into<Cow<'static, str>>,
 	) {
+		let protocol = protocol.into();
+
 		// This is the message that we will send to the remote as part of the initial handshake.
 		// At the moment, we force this to be an encoded `Roles`.
 		let handshake_message = Roles::from(&self.role).encode();
 
-		let list = self.substrate.register_notifications_protocol(engine_id, protocol_name, handshake_message);
+		let list = self.substrate.register_notifications_protocol(protocol.clone(), handshake_message);
 		for (remote, roles, notifications_sink) in list {
 			let role = reported_roles_to_observed_role(&self.role, remote, roles);
 			self.events.push_back(BehaviourOut::NotificationStreamOpened {
 				remote: remote.clone(),
-				engine_id,
+				protocol: protocol.clone(),
 				role,
 				notifications_sink: notifications_sink.clone(),
 			});
@@ -363,28 +364,28 @@ Behaviour<B, H> {
 			},
 			CustomMessageOutcome::NotificationStreamOpened { remote, protocols, roles, notifications_sink } => {
 				let role = reported_roles_to_observed_role(&self.role, &remote, roles);
-				for engine_id in protocols {
+				for protocol in protocols {
 					self.events.push_back(BehaviourOut::NotificationStreamOpened {
 						remote: remote.clone(),
-						engine_id,
+						protocol,
 						role: role.clone(),
 						notifications_sink: notifications_sink.clone(),
 					});
 				}
 			},
 			CustomMessageOutcome::NotificationStreamReplaced { remote, protocols, notifications_sink } =>
-				for engine_id in protocols {
+				for protocol in protocols {
 					self.events.push_back(BehaviourOut::NotificationStreamReplaced {
 						remote: remote.clone(),
-						engine_id,
+						protocol,
 						notifications_sink: notifications_sink.clone(),
 					});
 				},
 			CustomMessageOutcome::NotificationStreamClosed { remote, protocols } =>
-				for engine_id in protocols {
+				for protocol in protocols {
 					self.events.push_back(BehaviourOut::NotificationStreamClosed {
 						remote: remote.clone(),
-						engine_id,
+						protocol,
 					});
 				},
 			CustomMessageOutcome::NotificationsReceived { remote, messages } => {