Implement enumerated trie root throughout.

substrate/native-runtime/std/src/lib.rs

@@ -20,6 +20,7 @@
 extern crate environmental;
 extern crate polkadot_state_machine;
 extern crate polkadot_primitives as primitives;
+extern crate triehash;
 
 use std::fmt;
 use primitives::ed25519;
@@ -99,6 +100,13 @@ pub fn storage_root() -> [u8; 32] {
 	).unwrap_or([0u8; 32])
 }
 
+/// "Commit" all existing operations and get the resultant storage root.
+pub fn enumerated_trie_root(serialised_values: &[&[u8]]) -> [u8; 32] {
+	ext::with(|ext|
+		triehash::ordered_trie_root(serialised_values.iter().map(|s| s.to_vec())).0
+	).unwrap_or([0u8; 32])
+}
+
 /// Conduct a Keccak-256 hash of the given data.
 pub use primitives::{blake2_256, twox_128, twox_256};