Downward & Upward messages (#1266)

* Downward messages, the front-end.

* Move types around to make them accessible from Parachains

* Fix compilation

* Fix branch

* Make it compile for Cumulus

* Update the branch names

* Add default generic parameter

* Implement `Partialeq`

* Move upward messages into the `ValidationResult`

* Support disabling of the runtime api

* Update branch

* Adds support for handling downward messages

* Implement sending XCMP messages as up/downward messages

* service: update to latest ServiceBuilder changes

* Make it compile

* Initial commit

Forked at: ef2aa428d7
Parent branch: origin/master

* Update substrate branch to cecton-update-polkadot-substrate

* Update substrate & polkadot to cumulus-branch

* Reset branch

* Update primitives/src/parachain.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Update runtime/common/src/parachains.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Update runtime/common/src/parachains.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Minor fixes

* Fix wasm build

Co-authored-by: Gav Wood <gavin@parity.io>
Co-authored-by: André Silva <andre.beat@gmail.com>
Co-authored-by: Cecile Tonglet <cecile.tonglet@cecton.com>
Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

polkadot/parachain/test-parachains/tests/wasm_executor/mod.rs

@@ -16,9 +16,8 @@
 
 //! Basic parachain that adds a number as part of its state.
 
-use parachain;
-use crate::{adder, DummyExt};
-use crate::parachain::{
+use crate::adder;
+use parachain::{
 	primitives::{BlockData, ValidationParams},
 	wasm_executor::EXECUTION_TIMEOUT_SEC,
 };
@@ -40,7 +39,6 @@ fn terminates_on_timeout() {
 			relay_chain_height: 1,
 			code_upgrade_allowed: None,
 		},
-		DummyExt,
 		parachain::wasm_executor::ExecutionMode::RemoteTest(&pool),
 	);
 	match result {
@@ -70,7 +68,6 @@ fn parallel_execution() {
 			relay_chain_height: 1,
 			code_upgrade_allowed: None,
 		},
-		DummyExt,
 		parachain::wasm_executor::ExecutionMode::RemoteTest(&pool2),
 	).ok());
 	let _ = parachain::wasm_executor::validate_candidate(
@@ -83,7 +80,6 @@ fn parallel_execution() {
 			relay_chain_height: 1,
 			code_upgrade_allowed: None,
 		},
-		DummyExt,
 		parachain::wasm_executor::ExecutionMode::RemoteTest(&pool),
 	);
 	thread.join().unwrap();