Fixed up the bridge contract interfaces

packages/contracts/contracts/optimistic-ethereum/OVM/bridge/OVM_BaseCrossDomainMessenger.sol

@@ -41,6 +41,32 @@ contract OVM_BaseCrossDomainMessenger is iOVM_BaseCrossDomainMessenger {
         targetMessengerAddress = _targetMessengerAddress;
     }
 
+    /**
+     * Sends a cross domain message to the target messenger.
+     * @param _target Target contract address.
+     * @param _message Message to send to the target.
+     * @param _gasLimit Gas limit for the provided message.
+     */
+    function sendMessage(
+        address _target,
+        bytes memory _message,
+        uint256 _gasLimit
+    )
+        override
+        public
+    {
+        bytes memory xDomainCalldata = _getXDomainCalldata(
+            _target,
+            msg.sender,
+            _message,
+            messageNonce
+        );
+
+        _sendXDomainMessage(xDomainCalldata, _gasLimit);
+
+        messageNonce += 1;
+        sentMessages[keccak256(xDomainCalldata)] = true;
+    }
 
     /**********************
      * Internal Functions *
@@ -74,4 +100,19 @@ contract OVM_BaseCrossDomainMessenger is iOVM_BaseCrossDomainMessenger {
             _messageNonce
         );
     }
+
+    /**
+     * Sends a cross domain message.
+     * @param _message Message to send.
+     * @param _gasLimit Gas limit for the provided message.
+     */
+    function _sendXDomainMessage(
+        bytes memory _message,
+        uint256 _gasLimit
+    )
+        virtual
+        internal
+    {
+        revert("Implement me in child contracts!");
+    }
 }

packages/contracts/contracts/optimistic-ethereum/OVM/bridge/OVM_L1CrossDomainMessenger.sol

@@ -95,31 +95,6 @@ contract OVM_L1CrossDomainMessenger is iOVM_L1CrossDomainMessenger, OVM_BaseCros
         receivedMessages[keccak256(xDomainCalldata)] = true;
     }
 
-    /**
-     * Sends a cross domain message to the target messenger.
-     * @inheritdoc iOVM_L1CrossDomainMessenger
-     */
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint32 _gasLimit
-    )
-        override
-        public
-    {
-        bytes memory xDomainCalldata = _getXDomainCalldata(
-            _target,
-            msg.sender,
-            _message,
-            messageNonce
-        );
-
-        _sendXDomainMessage(xDomainCalldata, _gasLimit);
-
-        messageNonce += 1;
-        sentMessages[keccak256(xDomainCalldata)] = true;
-    }
-
     /**
      * Replays a cross domain message to the target messenger.
      * @inheritdoc iOVM_L1CrossDomainMessenger
@@ -255,8 +230,9 @@ contract OVM_L1CrossDomainMessenger is iOVM_L1CrossDomainMessenger, OVM_BaseCros
      */
     function _sendXDomainMessage(
         bytes memory _message,
-        uint32 _gasLimit
+        uint256 _gasLimit
     )
+        override
         internal
     {
         ovmL1ToL2TransactionQueue.enqueue(

packages/contracts/contracts/optimistic-ethereum/OVM/bridge/OVM_L2CrossDomainMessenger.sol

@@ -88,31 +88,6 @@ contract OVM_L2CrossDomainMessenger is iOVM_L2CrossDomainMessenger, OVM_BaseCros
         receivedMessages[keccak256(xDomainCalldata)] = true;
     }
 
-    /**
-     * Sends a cross domain message to the target messenger.
-     * @inheritdoc iOVM_L2CrossDomainMessenger
-     */
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint256 _gasLimit
-    )
-        override
-        public
-    {
-        bytes memory xDomainCalldata = _getXDomainCalldata(
-            _target,
-            msg.sender,
-            _message,
-            messageNonce
-        );
-
-        _sendXDomainMessage(xDomainCalldata, _gasLimit);
-
-        messageNonce += 1;
-        sentMessages[keccak256(xDomainCalldata)] = true;
-    }
-
 
     /**********************
      * Internal Functions *
@@ -142,6 +117,7 @@ contract OVM_L2CrossDomainMessenger is iOVM_L2CrossDomainMessenger, OVM_BaseCros
         bytes memory _message,
         uint256 _gasLimit
     )
+        override
         internal
     {
         ovmL2ToL1MessagePasser.passMessageToL1(_message);

packages/contracts/contracts/optimistic-ethereum/iOVM/bridge/iOVM_BaseCrossDomainMessenger.sol

@@ -18,4 +18,16 @@ interface iOVM_BaseCrossDomainMessenger {
     function setTargetMessengerAddress(
         address _targetMessengerAddress
     ) external;
+
+    /**
+     * Sends a cross domain message to the target messenger.
+     * @param _target Target contract address.
+     * @param _message Message to send to the target.
+     * @param _gasLimit Gas limit for the provided message.
+     */
+    function sendMessage(
+        address _target,
+        bytes memory _message,
+        uint256 _gasLimit
+    ) external;
 }

packages/contracts/contracts/optimistic-ethereum/iOVM/bridge/iOVM_L1CrossDomainMessenger.sol

@@ -46,18 +46,6 @@ interface iOVM_L1CrossDomainMessenger is iOVM_BaseCrossDomainMessenger {
         L2MessageInclusionProof memory _proof
     ) external;
 
-    /**
-     * Sends a cross domain message to the target messenger.
-     * @param _target Target contract address.
-     * @param _message Message to send to the target.
-     * @param _gasLimit Gas limit for the provided message.
-     */
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint32 _gasLimit
-    ) external;
-
     /**
      * Replays a cross domain message to the target messenger.
      * @param _target Target contract address.

packages/contracts/contracts/optimistic-ethereum/iOVM/bridge/iOVM_L2CrossDomainMessenger.sol

@@ -27,16 +27,4 @@ interface iOVM_L2CrossDomainMessenger is iOVM_BaseCrossDomainMessenger {
         bytes memory _message,
         uint256 _messageNonce
     ) external;
-
-    /**
-     * Sends a cross domain message to the target messenger.
-     * @param _target Target contract address.
-     * @param _message Message to send to the target.
-     * @param _gasLimit Gas limit for the provided message.
-     */
-    function sendMessage(
-        address _target,
-        bytes memory _message,
-        uint256 _gasLimit
-    ) external;
 }