Consensus Engines Implementation: Aura (#911)

* Generalize BlockImport

 - move ImportBlock, BlockOrigin, ImportResult into shared sr-primitives
 - let Consensus provide  and  traits again
 - update consensus traits to latest development
 - implement traits on client::Client, test_client::TestClient
 - update RHD to use the new import_block API

* Move ImportBlock into consensus-common
* Send import notification in aura tests
* Integrating aura into service
* Make Signatures more generic
* Aura Block Production with the given key
* run aura on the thread pool
* start at exact step start in aura
* Add needed wasm blob, in leiu of better solutions.
* Make API ids consistent with traits and bring upstream for sharing.
* Add decrease_free_balance to Balances module
* Encode `Metadata` once instead of two times
* Bitops include xor
* Upgrade key module.
* Default pages to somewhat bigger.
* Introduce upgrade key into node
* Add `Created` event

substrate/core/network/src/sync.rs

@@ -18,7 +18,8 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use protocol::Context;
 use network_libp2p::{Severity, NodeIndex};
-use client::{BlockStatus, BlockOrigin, ClientInfo};
+use client::{BlockStatus, ClientInfo};
+use consensus::BlockOrigin;
 use client::error::Error as ClientError;
 use blocks::{self, BlockCollection};
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, As, NumberFor};
@@ -77,6 +78,17 @@ pub struct Status<B: BlockT> {
 	pub best_seen_block: Option<NumberFor<B>>,
 }
 
+impl<B: BlockT> Status<B> {
+	/// Whether the synchronization status is doing major downloading work or
+	/// is near the head of the chain.
+	pub fn is_major_syncing(&self) -> bool {
+		match self.state {
+			SyncState::Idle => false,
+			SyncState::Downloading => true,
+		}
+	}
+}
+
 impl<B: BlockT> ChainSync<B> {
 	/// Create a new instance.
 	pub(crate) fn new(role: Roles, info: &ClientInfo<B>, import_queue: Arc<ImportQueue<B>>) -> Self {