consensus: handle justification sync for blocks authored locally (#8698)

* consensus: add trait to control justification sync process

* network: implement JustificationSyncLink for NetworkService

* slots: handle justification sync in slot worker

* babe: fix slot worker instantiation

* aura: fix slot worker instantiation

* pow: handle justification sync in miner

* babe: fix tests

* aura: fix tests

* node: fix compilation

* node-template: fix compilation

* consensus: rename justification sync link parameter

* aura: fix test compilation

* consensus: slots: move JustificationSyncLink out of on_slot

substrate/client/consensus/pow/src/worker.rs

@@ -18,8 +18,12 @@
 
 use std::{pin::Pin, time::Duration, collections::HashMap, borrow::Cow};
 use sc_client_api::ImportNotifications;
-use sp_runtime::{DigestItem, traits::Block as BlockT, generic::BlockId};
 use sp_consensus::{Proposal, BlockOrigin, BlockImportParams, import_queue::BoxBlockImport};
+use sp_runtime::{
+	generic::BlockId,
+	traits::{Block as BlockT, Header as HeaderT},
+	DigestItem,
+};
 use futures::{prelude::*, task::{Context, Poll}};
 use futures_timer::Delay;
 use log::*;
@@ -57,18 +61,22 @@ pub struct MiningWorker<
 	Block: BlockT,
 	Algorithm: PowAlgorithm<Block>,
 	C: sp_api::ProvideRuntimeApi<Block>,
-	Proof
+	L: sp_consensus::JustificationSyncLink<Block>,
+	Proof,
 > {
 	pub(crate) build: Option<MiningBuild<Block, Algorithm, C, Proof>>,
 	pub(crate) algorithm: Algorithm,
 	pub(crate) block_import: BoxBlockImport<Block, sp_api::TransactionFor<C, Block>>,
+	pub(crate) justification_sync_link: L,
 }
 
-impl<Block, Algorithm, C, Proof> MiningWorker<Block, Algorithm, C, Proof> where
+impl<Block, Algorithm, C, L, Proof> MiningWorker<Block, Algorithm, C, L, Proof>
+where
 	Block: BlockT,
 	C: sp_api::ProvideRuntimeApi<Block>,
 	Algorithm: PowAlgorithm<Block>,
 	Algorithm::Difficulty: 'static + Send,
+	L: sp_consensus::JustificationSyncLink<Block>,
 	sp_api::TransactionFor<C, Block>: Send + 'static,
 {
 	/// Get the current best hash. `None` if the worker has just started or the client is doing
@@ -139,8 +147,11 @@ impl<Block, Algorithm, C, Proof> MiningWorker<Block, Algorithm, C, Proof> where
 				Box::new(intermediate) as Box<_>,
 			);
 
+			let header = import_block.post_header();
 			match self.block_import.import_block(import_block, HashMap::default()).await {
-				Ok(_) => {
+				Ok(res) => {
+					res.handle_justification(&header.hash(), *header.number(), &mut self.justification_sync_link);
+
 					info!(
 						target: "pow",
 						"✅ Successfully mined block on top of: {}",