Implement missed From<UncheckedExtrinsic> for OpaqueExtrinsic (parity…

…tech#554)

* Implement missed From<UncheckedExtrinsic> for OpaqueExtrinsic

* Fix based on review

primitives/self-contained/src/unchecked_extrinsic.rs

@@ -11,7 +11,7 @@ use sp_runtime::{
 		SignedExtension,
 	},
 	transaction_validity::{InvalidTransaction, TransactionValidityError},
-	RuntimeDebug,
+	OpaqueExtrinsic, RuntimeDebug,
 };
 
 /// A extrinsic right from the external world. This is unchecked and so
@@ -165,3 +165,16 @@ impl<'a, Address: Decode, Signature: Decode, Call: Decode, Extra: SignedExtensio
 			.map(Self)
 	}
 }
+
+impl<Address, Call, Signature, Extra> From<UncheckedExtrinsic<Address, Call, Signature, Extra>>
+	for OpaqueExtrinsic
+where
+	Address: Encode,
+	Signature: Encode,
+	Call: Encode,
+	Extra: SignedExtension,
+{
+	fn from(extrinsic: UncheckedExtrinsic<Address, Call, Signature, Extra>) -> Self {
+		extrinsic.0.into()
+	}
+}