override conversion rate in estimate-message-fee RPC (#1189)

bridges/bin/rialto/runtime/src/lib.rs

@@ -53,7 +53,7 @@ use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, Block as BlockT, Keccak256, NumberFor, OpaqueKeys},
 	transaction_validity::{TransactionSource, TransactionValidity},
-	ApplyExtrinsicResult, FixedPointNumber, MultiSignature, MultiSigner, Perquintill,
+	ApplyExtrinsicResult, FixedPointNumber, FixedU128, MultiSignature, MultiSigner, Perquintill,
 };
 use sp_std::{collections::btree_map::BTreeMap, prelude::*};
 #[cfg(feature = "std")]
@@ -892,10 +892,12 @@ impl_runtime_apis! {
 		fn estimate_message_delivery_and_dispatch_fee(
 			_lane_id: bp_messages::LaneId,
 			payload: ToMillauMessagePayload,
+			millau_to_this_conversion_rate: Option<FixedU128>,
 		) -> Option<Balance> {
 			estimate_message_dispatch_and_delivery_fee::<WithMillauMessageBridge>(
 				&payload,
 				WithMillauMessageBridge::RELAYER_FEE_PERCENT,
+				millau_to_this_conversion_rate,
 			).ok()
 		}