feat: add L2ProxyAdmin

packages/contracts-bedrock/interfaces/L2/IL2ContractsManager.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+/// @title IL2ContractsManager
+/// @notice Interface for the L2ContractsManager contract.
+interface IL2ContractsManager {
+    /// @notice Executes the upgrade for all predeploys.
+    /// @dev This function MUST be called via DELEGATECALL from the L2ProxyAdmin.
+    function upgrade() external;
+}

packages/contracts-bedrock/interfaces/L2/IL2ProxyAdmin.sol

@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+// Interfaces
+import { IProxyAdmin } from "interfaces/universal/IProxyAdmin.sol";
+import { ISemver } from "interfaces/universal/ISemver.sol";
+
+/// @title IL2ProxyAdmin
+interface IL2ProxyAdmin is IProxyAdmin, ISemver {
+    /// @notice Emitted when the predeploys are upgraded.
+    /// @param l2ContractsManager Address of the L2ContractsManager contract.
+    event PredeploysUpgraded(address indexed l2ContractsManager);
+
+    /// @notice Thrown when the caller is not the depositor account.
+    error L2ProxyAdmin__Unauthorized();
+
+    /// @notice Thrown when the upgrade fails.
+    error L2ProxyAdmin__UpgradeFailed(bytes data);
+
+    function __constructor__(address _owner) external;
+    /// @notice Upgrades the predeploys via delegatecall to the L2ContractsManager contract.
+    /// @param _l2ContractsManager Address of the L2ContractsManager contract.
+    function upgradePredeploys(address _l2ContractsManager) external;
+}

packages/contracts-bedrock/scripts/L2Genesis.s.sol

@@ -202,7 +202,7 @@ contract L2Genesis is Script {
 
     /// @notice Set up the accounts that correspond to the predeploys.
     ///         The Proxy bytecode should be set. All proxied predeploys should have
-    ///         the 1967 admin slot set to the ProxyAdmin predeploy. All defined predeploys
+    ///         the 1967 admin slot set to the L2ProxyAdmin predeploy. All defined predeploys
     ///         should have their implementations set.
     ///         Warning: the predeploy accounts have contract code, but 0 nonce value, contrary
     ///         to the expected nonce of 1 per EIP-161. This is because the legacy go genesis
@@ -249,7 +249,7 @@ contract L2Genesis is Script {
         setL1Block(_input.useCustomGasToken); // 15
         setL2ToL1MessagePasser(_input.useCustomGasToken); // 16
         setOptimismMintableERC721Factory(_input); // 17
-        setProxyAdmin(_input); // 18
+        setL2ProxyAdmin(_input); // 18
         setBaseFeeVault(_input); // 19
         setL1FeeVault(_input); // 1A
         setOperatorFeeVault(_input); // 1B
@@ -272,12 +272,13 @@ contract L2Genesis is Script {
 
     function setInteropPredeployProxies() internal { }
 
-    function setProxyAdmin(Input memory _input) internal {
-        // Note the ProxyAdmin implementation itself is behind a proxy that owns itself.
+    function setL2ProxyAdmin(Input memory _input) internal {
+        // Note the L2ProxyAdmin implementation itself is behind a proxy that owns itself.
         address impl = _setImplementationCode(Predeploys.PROXY_ADMIN);
 
         bytes32 _ownerSlot = bytes32(0);
 
+        // TODO(#19182): Remove this once the L2ProxyAdmin is initializable.
         // there is no initialize() function, so we just set the storage manually.
         vm.store(Predeploys.PROXY_ADMIN, _ownerSlot, bytes32(uint256(uint160(_input.opChainProxyAdminOwner))));
         // update the proxy to not be uninitialized (although not standard initialize pattern)