op-node: higher level api for hashing output root proof

op-node/rollup/output_root.go

 package rollup
 
 import (
+	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
+// ComputeL2OutputRoot computes the L2 output root
 func ComputeL2OutputRoot(l2OutputRootVersion eth.Bytes32, blockHash common.Hash, blockRoot common.Hash, storageRoot common.Hash) eth.Bytes32 {
 	digest := crypto.Keccak256Hash(
 		l2OutputRootVersion[:],
@@ -15,3 +17,13 @@ func ComputeL2OutputRoot(l2OutputRootVersion eth.Bytes32, blockHash common.Hash,
 	)
 	return eth.Bytes32(digest)
 }
+
+// HashOutputRootProof computes the hash of the output root proof
+func HashOutputRootProof(proof *bindings.TypesOutputRootProof) eth.Bytes32 {
+	return ComputeL2OutputRoot(
+		proof.Version,
+		proof.StateRoot,
+		proof.MessagePasserStorageRoot,
+		proof.LatestBlockhash,
+	)
+}