Fix registry interface

KIPs/kip-149.md

@@ -62,14 +62,7 @@ The registry should have data for the pre-deployed system contracts as soon as i
 ```solidity
 pragma solidity ^0.8.0;
 
-abstract contract Registry {
-    /* ========== TYPES ========== */
-    /// @dev Struct of system contracts
-    struct Record {
-        address addr;
-        uint256 activation;
-    }
-
+abstract contract RegistryInterface {
     /* ========== VARIABLES ========== */
     /// The following variables are baked in the interface because their storage layout matters in protocol consensus 
     /// when inject initial states (pre-deployed system contracts, owner) of the Registry.
@@ -80,7 +73,14 @@ abstract contract Registry {
     string[] public names;
 
     /// @dev Owner of contract
-    address private _owner;
+    address internal _owner;
+
+    /* ========== TYPES ========== */
+    /// @dev Struct of system contracts
+    struct Record {
+        address addr;
+        uint256 activation;
+    }
 
     /* ========== EVENTS ========== */
     /// @dev Emitted when the contract owner is updated by `transferOwnership`.
@@ -91,24 +91,24 @@ abstract contract Registry {
 
     /* ========== MUTATORS ========== */
     /// @dev Registers a new system contract.
-    function register(string memory name, address addr, uint256 activation) external;
+    function register(string memory name, address addr, uint256 activation) external virtual;
     
     /// @dev Transfers ownership to newOwner.
-    function transferOwnership(address newOwner) external;
+    function transferOwnership(address newOwner) external virtual;
 
     /* ========== GETTERS ========== */
     /// @dev Returns an address for active system contracts registered as name if exists.
     ///  It returns a zero address when there's no active system contract with name.
-    function getActiveAddr(string memory name) external returns (address);
+    function getActiveAddr(string memory name) external virtual returns (address);
   
     /// @dev Returns all system contracts registered as name.
-    function getAllRecords(string memory name) external view returns (Record[] memory);
+    function getAllRecords(string memory name) external virtual view returns (Record[] memory);
     
     /// @dev Returns all names of registered system contracts.
-    function getAllNames() external view returns (string[] memory);
+    function getAllNames() external virtual view returns (string[] memory);
     
     /// @dev Returns owner of contract.
-    function owner() external view returns (address);
+    function owner() external virtual view returns (address);
 }
 ```