Adds a session getter to historical proofs

bin/node/runtime/src/lib.rs

@@ -82,7 +82,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to 0. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 227,
+	spec_version: 228,
 	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 };

frame/session/src/historical.rs

@@ -266,6 +266,13 @@ pub struct Proof {
 	trie_nodes: Vec<Vec<u8>>,
 }
 
+impl Proof {
+	/// Returns a session this proof was generated for.
+	pub fn session(&self) -> SessionIndex {
+		self.session
+	}
+}
+
 impl<T: Trait, D: AsRef<[u8]>> frame_support::traits::KeyOwnerProofSystem<(KeyTypeId, D)>
 	for Module<T>
 {