Merge txpool-runtime-api with txpool-api (#4320)

* Remove transaction-pool-runtime-api

* Merge runtime-api with transaction-pool.

substrate/primitives/transaction-pool/src/runtime_api.rs

@@ -0,0 +1,28 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Tagged Transaction Queue Runtime API.
+
+use sp_runtime::transaction_validity::TransactionValidity;
+use sp_runtime::traits::Block as BlockT;
+
+sp_api::decl_runtime_apis! {
+	/// The `TaggedTransactionQueue` api trait for interfering with the transaction queue.
+	pub trait TaggedTransactionQueue {
+		/// Validate the given transaction.
+		fn validate_transaction(tx: <Block as BlockT>::Extrinsic) -> TransactionValidity;
+	}
+}