Refactor GlobalExitRoot contracts for dovereign chains

contracts/PolygonZkEVMGlobalExitRootL2.sol

@@ -2,12 +2,16 @@
 
 pragma solidity 0.8.20;
 import "./interfaces/IBasePolygonZkEVMGlobalExitRoot.sol";
+import {PolygonAccessControlUpgradeable} from "./v2/lib/PolygonAccessControlUpgradeable.sol";
 
 /**
  * Contract responsible for managing the exit roots for the L2 and global exit roots
  * The special zkRom variables will be accessed and updated directly by the zkRom
  */
-contract PolygonZkEVMGlobalExitRootL2 is IBasePolygonZkEVMGlobalExitRoot {
+contract PolygonZkEVMGlobalExitRootL2 is
+    IBasePolygonZkEVMGlobalExitRoot,
+    PolygonAccessControlUpgradeable
+{
     /////////////////////////////
     // Special zkRom variables
     ////////////////////////////
@@ -27,18 +31,25 @@ contract PolygonZkEVMGlobalExitRootL2 is IBasePolygonZkEVMGlobalExitRoot {
     // PolygonZkEVM Bridge address
     address public immutable bridgeAddress;
 
+    /**
+     * @dev This empty reserved space is put in place to allow future versions to add new
+     * variables without shifting down storage in the inheritance chain.
+     */
+    uint256[50] private _gap;
+
     /**
      * @param _bridgeAddress PolygonZkEVMBridge contract address
      */
     constructor(address _bridgeAddress) {
         bridgeAddress = _bridgeAddress;
+        _disableInitializers();
     }
 
     /**
      * @notice Update the exit root of one of the networks and the global exit root
      * @param newRoot new exit tree root
      */
-    function updateExitRoot(bytes32 newRoot) external {
+    function updateExitRoot(bytes32 newRoot) external virtual {
         if (msg.sender != bridgeAddress) {
             revert OnlyAllowedContracts();
         }

contracts/v2/sovereignChains/GlobalExitRootManagerL2SovereignChain.sol

@@ -3,36 +3,17 @@
 pragma solidity 0.8.20;
 import "../../interfaces/IBasePolygonZkEVMGlobalExitRoot.sol";
 import {PolygonAccessControlUpgradeable} from "../lib/PolygonAccessControlUpgradeable.sol";
+import "../../PolygonZkEVMGlobalExitRootL2.sol";
 
 /**
  * Contract responsible for managing the exit roots for the Sovereign chains and global exit roots
  */
-contract GlobalExitRootManagerL2SovereignChain is
-    PolygonAccessControlUpgradeable,
-    IBasePolygonZkEVMGlobalExitRoot
-{
-    // Store every global exit root: Root --> timestamp
-    mapping(bytes32 => uint256) public globalExitRootMap;
-
-    // Rollup exit root will be updated for every Sovereign chain call
-    bytes32 public lastRollupExitRoot;
-
-    // Sovereign chain Bridge address
-    address public immutable bridgeAddress;
-
+contract GlobalExitRootManagerL2SovereignChain is PolygonZkEVMGlobalExitRootL2 {
     /**
      * @dev Emitted when a new global exit root is inserted
      */
     event InsertGlobalExitRoot(bytes32 indexed newGlobalExitRoot);
 
-    /**
-     * @param _bridgeAddress BridgeL2SovereignChain contract address
-     */
-    constructor(address _bridgeAddress) {
-        bridgeAddress = _bridgeAddress;
-        _disableInitializers();
-    }
-
     /**
      * @notice Only allows a function to be callable if its called by coinbase (trusted sequencer in sovereign chains)
      */
@@ -53,11 +34,20 @@ contract GlobalExitRootManagerL2SovereignChain is
         _;
     }
 
+    /**
+     * @param _bridgeAddress PolygonZkEVMBridge contract address
+     */
+    constructor(
+        address _bridgeAddress
+    ) PolygonZkEVMGlobalExitRootL2(_bridgeAddress) {}
+
     /**
      * @notice Update the exit root of one of the networks and the global exit root
      * @param newRoot new exit tree root
      */
-    function updateExitRoot(bytes32 newRoot) external onlyBridgeAddress() {
+    function updateExitRoot(
+        bytes32 newRoot
+    ) external override onlyBridgeAddress {
         lastRollupExitRoot = newRoot;
     }