Fix transaction pruning in tx-pool (#6276)

The `tree_route` generated by the import notification is only from the
old best block to the new best parent. This means, it does not contain
the new best block in `enacted()`. We need to prune the transactions of
the new best block "manually" to fix this bug.

Besides that, this pr also changed the `id` parameter of the `NewBlock`
chain event to `hash`. The hash of a block is unique in contrast to the
block number. (Block id can either be number or hash)

substrate/client/api/src/client.rs

@@ -234,7 +234,7 @@ pub struct BlockImportNotification<Block: BlockT> {
 	pub header: Block::Header,
 	/// Is this the new best block.
 	pub is_new_best: bool,
-	/// Tree route from old best to new best.
+	/// Tree route from old best to new best parent.
 	///
 	/// If `None`, there was no re-org while importing.
 	pub tree_route: Option<Arc<sp_blockchain::TreeRoute<Block>>>,
@@ -248,3 +248,22 @@ pub struct FinalityNotification<Block: BlockT> {
 	/// Imported block header.
 	pub header: Block::Header,
 }
+
+impl<B: BlockT> From<BlockImportNotification<B>> for sp_transaction_pool::ChainEvent<B> {
+	fn from(n: BlockImportNotification<B>) -> Self {
+		Self::NewBlock {
+			is_new_best: n.is_new_best,
+			hash: n.hash,
+			header: n.header,
+			tree_route: n.tree_route,
+		}
+	}
+}
+
+impl<B: BlockT> From<FinalityNotification<B>> for sp_transaction_pool::ChainEvent<B> {
+	fn from(n: FinalityNotification<B>) -> Self {
+		Self::Finalized {
+			hash: n.hash,
+		}
+	}
+}