maint: add interfaces for legacy contracts

Adds interfaces for the contracts inside of /legacy. Interfaces
are not included for ResolvedDelegateProxy (does not have external
functions) or for LegacyMintableERC20 (interface already exists
inside of another file).

packages/contracts-bedrock/src/legacy/interfaces/IAddressManager.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+/// @title IAddressManager
+/// @notice Interface for AddressManager.
+interface IAddressManager {
+    /// @notice Emitted when an address is modified in the registry.
+    /// @param name       String name being set in the registry.
+    /// @param newAddress Address set for the given name.
+    /// @param oldAddress Address that was previously set for the given name.
+    event AddressSet(string indexed name, address newAddress, address oldAddress);
+
+    /// @notice Changes the address associated with a particular name.
+    /// @param _name    String name to associate an address with.
+    /// @param _address Address to associate with the name.
+    function setAddress(string memory _name, address _address) external;
+
+    /// @notice Retrieves the address associated with a given name.
+    /// @param _name Name to retrieve an address for.
+    /// @return Address associated with the given name.
+    function getAddress(string memory _name) external view returns (address);
+}

packages/contracts-bedrock/src/legacy/interfaces/IDeployerWhitelist.sol

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { ISemver } from "src/universal/ISemver.sol";
+
+/// @title IDeployerWhitelist
+/// @notice Interface for the DeployerWhitelist contract.
+interface IDeployerWhitelist is ISemver {
+    /// @notice Emitted when the owner of this contract changes.
+    /// @param oldOwner Address of the previous owner.
+    /// @param newOwner Address of the new owner.
+    event OwnerChanged(address oldOwner, address newOwner);
+
+    /// @notice Emitted when the whitelist status of a deployer changes.
+    /// @param deployer    Address of the deployer.
+    /// @param whitelisted Boolean indicating whether the deployer is whitelisted.
+    event WhitelistStatusChanged(address deployer, bool whitelisted);
+
+    /// @notice Emitted when the whitelist is disabled.
+    /// @param oldOwner Address of the final owner of the whitelist.
+    event WhitelistDisabled(address oldOwner);
+
+    /// @notice Address of the owner of this contract. Note that when this address is set to
+    ///         address(0), the whitelist is disabled.
+    function owner() external view returns (address);
+
+    /// @notice Mapping of deployer addresses to boolean whitelist status.
+    function whitelist(address _deployer) external view returns (bool);
+
+    /// @notice Adds or removes an address from the deployment whitelist.
+    /// @param _deployer      Address to update permissions for.
+    /// @param _isWhitelisted Whether or not the address is whitelisted.
+    function setWhitelistedDeployer(address _deployer, bool _isWhitelisted) external;
+
+    /// @notice Updates the owner of this contract.
+    /// @param _owner Address of the new owner.
+    function setOwner(address _owner) external;
+
+    /// @notice Permanently enables arbitrary contract deployment and deletes the owner.
+    function enableArbitraryContractDeployment() external;
+
+    /// @notice Checks whether an address is allowed to deploy contracts.
+    /// @param _deployer Address to check.
+    /// @return Whether or not the address can deploy contracts.
+    function isDeployerAllowed(address _deployer) external view returns (bool);
+}

packages/contracts-bedrock/src/legacy/interfaces/IL1BlockNumber.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { ISemver } from "src/universal/ISemver.sol";
+
+/// @title IL1BlockNumber
+/// @notice Interface for the L1BlockNumber contract.
+interface IL1BlockNumber is ISemver {
+    /// @notice Retrieves the latest L1 block number.
+    /// @return Latest L1 block number.
+    function getL1BlockNumber() external view returns (uint256);
+}

packages/contracts-bedrock/src/legacy/interfaces/IL1ChugSplashProxy.sol

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+/// @title IL1ChugSplashProxy
+/// @notice Interface for the L1ChugSplashProxy contract.
+interface IL1ChugSplashProxy {
+    /// @notice Sets the code that should be running behind this proxy.
+    /// @param _code New contract code to run inside this contract.
+    function setCode(bytes memory _code) external;
+
+    /// @notice Modifies some storage slot within the proxy contract. Gives us a lot of power to
+    ///         perform upgrades in a more transparent way. Only callable by the owner.
+    /// @param _key   Storage key to modify.
+    /// @param _value New value for the storage key.
+    function setStorage(bytes32 _key, bytes32 _value) external;
+
+    /// @notice Changes the owner of the proxy contract. Only callable by the owner.
+    /// @param _owner New owner of the proxy contract.
+    function setOwner(address _owner) external;
+
+    /// @notice Queries the owner of the proxy contract. Can only be called by the owner OR by
+    ///         making an eth_call and setting the "from" address to address(0).
+    /// @return Owner address.
+    function getOwner() external returns (address);
+
+    /// @notice Queries the implementation address. Can only be called by the owner OR by making an
+    ///         eth_call and setting the "from" address to address(0).
+    /// @return Implementation address.
+    function getImplementation() external returns (address);
+}

packages/contracts-bedrock/src/legacy/interfaces/ILegacyMessagePasser.sol

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { ISemver } from "src/universal/ISemver.sol";
+
+/// @title ILegacyMessagePasser
+/// @notice Interface for the LegacyMessagePasser contract.
+interface ILegacyMessagePasser is ISemver {
+    /// @notice Mapping of sent message hashes to boolean status.
+    function sentMessages(bytes32 _messageHash) external view returns (bool);
+
+    /// @notice Passes a message to L1.
+    /// @param _message Message to pass to L1.
+    function passMessageToL1(bytes memory _message) external;
+}