Parachain Consensus abstractions (#329)

* Move consensus to consensus-common crate

* Move the parachain consensus out of the collator

* Add first relay chain consensus stuff

* Remove some warnings

* Fix more stuff

* Fix collator test

* Change `ParachainConsensus` to take a mutable self

* Make everything compile

* Feedback

cumulus/rococo-parachains/Cargo.toml

@@ -56,7 +56,7 @@ sp-offchain = { git = "https://github.com/paritytech/substrate", branch = "maste
 jsonrpc-core = "15.1.0"
 
 # Cumulus dependencies
-cumulus-client-consensus = { path = "../client/consensus" }
+cumulus-client-consensus-relay-chain = { path = "../client/consensus/relay-chain" }
 cumulus-client-collator = { path = "../client/collator" }
 cumulus-client-service = { path = "../client/service" }
 cumulus-client-network = { path = "../client/network" }

cumulus/rococo-parachains/src/service.rs

@@ -19,6 +19,7 @@ use cumulus_primitives_core::ParaId;
 use cumulus_client_service::{
 	prepare_node_config, start_collator, start_full_node, StartCollatorParams, StartFullNodeParams,
 };
+use cumulus_client_consensus_relay_chain::{build_relay_chain_consensus, BuildRelayChainConsensusParams};
 use parachain_runtime::RuntimeApi;
 use polkadot_primitives::v0::CollatorPair;
 use rococo_parachain_primitives::Block;
@@ -70,7 +71,7 @@ pub fn new_partial(
 		client.clone(),
 	);
 
-	let import_queue = cumulus_client_consensus::import_queue::import_queue(
+	let import_queue = cumulus_client_consensus_relay_chain::import_queue(
 		client.clone(),
 		client.clone(),
 		inherent_data_providers.clone(),
@@ -188,22 +189,26 @@ where
 		);
 		let spawner = task_manager.spawn_handle();
 
-		let polkadot_backend = polkadot_full_node.backend.clone();
+		let parachain_consensus = build_relay_chain_consensus(BuildRelayChainConsensusParams {
+			para_id: id,
+			proposer_factory,
+			inherent_data_providers: params.inherent_data_providers,
+			block_import: client.clone(),
+			relay_chain_client: polkadot_full_node.client.clone(),
+			relay_chain_backend: polkadot_full_node.backend.clone(),
+		});
 
 		let params = StartCollatorParams {
 			para_id: id,
-			block_import: client.clone(),
-			proposer_factory,
-			inherent_data_providers: params.inherent_data_providers,
 			block_status: client.clone(),
 			announce_block,
 			client: client.clone(),
 			task_manager: &mut task_manager,
 			collator_key,
-			polkadot_full_node,
+			relay_chain_full_node: polkadot_full_node,
 			spawner,
 			backend,
-			polkadot_backend,
+			parachain_consensus,
 		};
 
 		start_collator(params).await?;