refactor[contracts]: Remove old mock contracts (#600)

* refactor[contracts]: Remove old mock contracts

* chore[contracts]: Add changeset

.changeset/eleven-books-camp.md

+---
+"@eth-optimism/contracts": patch
+---
+
+Removed two old mock contracts

packages/contracts/contracts/optimistic-ethereum/mockOVM/bridge/mockOVM_CrossDomainMessenger.sol

-// SPDX-License-Identifier: MIT
-pragma solidity >0.5.0 <0.8.0;
-pragma experimental ABIEncoderV2;
-
-/* Contract Imports */
-import { iAbs_BaseCrossDomainMessenger } from "../../iOVM/bridge/messaging/iAbs_BaseCrossDomainMessenger.sol";
-
-/**
- * @title mockOVM_CrossDomainMessenger
- */
-contract mockOVM_CrossDomainMessenger is iAbs_BaseCrossDomainMessenger {
-
-    /***********
-     * Structs *
-     ***********/
-
-    struct ReceivedMessage {
-        uint256 timestamp;
-        address target;
-        address sender;
-        bytes message;
-        uint256 messageNonce;
-        uint32 gasLimit;
-    }
-
-
-    /**********************
-     * Contract Variables *
-     **********************/
-
-    ReceivedMessage[] internal fullReceivedMessages;
-    address internal targetMessengerAddress;
-    uint256 internal lastRelayedMessage;
-    uint256 internal delay;
-    uint256 public messageNonce;
-    address override public xDomainMessageSender;
-
-
-    /***************
-     * Constructor *
-     ***************/
-
-    /**
-     * @param _delay Time in seconds before a message can be relayed.
-     */
-    constructor(
-        uint256 _delay
-    )
-    {
-        delay = _delay;
-    }
-
-
-    /********************
-     * Public Functions *
-     ********************/
-
-    /**
-     * Sets the target messenger address.
-     * @dev Currently, this function is public and therefore allows anyone to modify the target
-     *      messenger for a given xdomain messenger contract. Obviously this shouldn't be allowed,
-     *      but we still need to determine an adequate mechanism for updating this address.
-     * @param _targetMessengerAddress New messenger address.
-     */
-    function setTargetMessengerAddress(
-        address _targetMessengerAddress
-    )
-        public
-    {
-        targetMessengerAddress = _targetMessengerAddress;
-    }
-
-    /**
-     * Sends a message to another mock xdomain messenger.
-     * @param _target Target for the message.
-     * @param _message Message to send.
-     * @param _gasLimit Amount of gas to send with the call.
-     */
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint32 _gasLimit
-    )
-        override
-        public
-    {
-        mockOVM_CrossDomainMessenger targetMessenger = mockOVM_CrossDomainMessenger(
-            targetMessengerAddress
-        );
-
-        // Just send it over!
-        targetMessenger.receiveMessage(ReceivedMessage({
-            timestamp: block.timestamp,
-            target: _target,
-            sender: msg.sender,
-            message: _message,
-            messageNonce: messageNonce,
-            gasLimit: _gasLimit
-        }));
-
-        messageNonce += 1;
-    }
-
-    /**
-     * Receives a message to be sent later.
-     * @param _message Message to send later.
-     */
-    function receiveMessage(
-        ReceivedMessage memory _message
-    )
-        public
-    {
-        fullReceivedMessages.push(_message);
-    }
-
-    /**
-     * Checks whether we have messages to relay.
-     * @param _exists Whether or not we have more messages to relay.
-     */
-    function hasNextMessage()
-        public
-        view
-        returns (
-            bool _exists
-        )
-    {
-        return fullReceivedMessages.length > lastRelayedMessage;
-    }
-
-    /**
-     * Relays the last received message not yet relayed.
-     */
-    function relayNextMessage()
-        public
-    {
-        require(hasNextMessage(), "No pending messages to relay");
-        ReceivedMessage memory nextMessage = fullReceivedMessages[lastRelayedMessage];
-        require(nextMessage.timestamp + delay < block.timestamp, "Message is not ready to be relayed. The delay period is not up yet!");
-
-        xDomainMessageSender = nextMessage.sender;
-        (bool success,) = nextMessage.target.call{gas: nextMessage.gasLimit}(nextMessage.message);
-        require(success, "Cross-domain message call reverted. Did you set your gas limit high enough?");
-        lastRelayedMessage += 1;
-    }
-}

packages/contracts/contracts/optimistic-ethereum/mockOVM/bridge/mockOVM_GenericCrossDomainMessenger.sol

-// SPDX-License-Identifier: MIT
-pragma solidity >0.5.0 <0.8.0;
-pragma experimental ABIEncoderV2;
-
-/**
- * @title mockOVM_GenericCrossDomainMessenger
- * @dev An experimental alternative mock for local testing.
- */
-contract mockOVM_GenericCrossDomainMessenger {
-    address public xDomainMessageSender;
-
-    event SentMessage(
-        address _sender,
-        address _target,
-        bytes _message,
-        uint256 _gasLimit
-    );
-
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint32 _gasLimit
-    )
-        public
-    {
-        emit SentMessage(
-            msg.sender,
-            _target,
-            _message,
-            _gasLimit
-        );
-    }
-
-    function relayMessage(
-        address _sender,
-        address _target,
-        bytes memory _message,
-        uint256 _gasLimit
-    )
-        public
-    {
-        xDomainMessageSender = _sender;
-        (bool success, ) = _target.call{gas: _gasLimit}(_message);
-        require(success, "Cross-domain message call reverted. Did you set your gas limit high enough?");
-        xDomainMessageSender = address(0);
-    }
-}