refactor[contracts]: Import OZ contracts directly (#609)

* refactor[contracts]: Import contracts directly from OZ

* chore[contracts]: Add changeset

* fix[integration-tests]: Update gas estimate

.changeset/odd-cows-fry.md

+---
+"@eth-optimism/contracts": patch
+---
+
+Removes copies of OZ contracts in favor of importing from OZ directly

integration-tests/test/native-eth.spec.ts

@@ -51,7 +51,7 @@ describe('Native ETH Integration Tests', async () => {
     it('Should estimate gas for ETH withdraw', async () => {
       const amount = utils.parseEther('0.5')
       const gas = await env.ovmEth.estimateGas.withdraw(amount)
-      expect(gas).to.be.deep.eq(BigNumber.from(503749))
+      expect(gas).to.be.deep.eq(BigNumber.from(503789))
     })
   })
 

packages/contracts/contracts/optimistic-ethereum/OVM/bridge/messaging/Abs_BaseCrossDomainMessenger.sol

@@ -5,8 +5,8 @@ pragma experimental ABIEncoderV2;
 /* Interface Imports */
 import { iAbs_BaseCrossDomainMessenger } from "../../../iOVM/bridge/messaging/iAbs_BaseCrossDomainMessenger.sol";
 
-/* Library Imports */
-import { Lib_ReentrancyGuard } from "../../../libraries/utils/Lib_ReentrancyGuard.sol";
+/* External Imports */
+import { ReentrancyGuard } from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
 
 /**
  * @title Abs_BaseCrossDomainMessenger
@@ -17,7 +17,7 @@ import { Lib_ReentrancyGuard } from "../../../libraries/utils/Lib_ReentrancyGuar
  * Compiler used: defined by child contract
  * Runtime target: defined by child contract
  */
-abstract contract Abs_BaseCrossDomainMessenger is iAbs_BaseCrossDomainMessenger, Lib_ReentrancyGuard {
+abstract contract Abs_BaseCrossDomainMessenger is iAbs_BaseCrossDomainMessenger, ReentrancyGuard {
 
     /*************
      * Constants *
@@ -44,7 +44,7 @@ abstract contract Abs_BaseCrossDomainMessenger is iAbs_BaseCrossDomainMessenger,
      * Constructor *
      ***************/
 
-    constructor() Lib_ReentrancyGuard() {}
+    constructor() ReentrancyGuard() {}
 
 
     /********************

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

@@ -7,7 +7,6 @@ import { Lib_OVMCodec } from "../../../libraries/codec/Lib_OVMCodec.sol";
 import { Lib_AddressResolver } from "../../../libraries/resolver/Lib_AddressResolver.sol";
 import { Lib_AddressManager } from "../../../libraries/resolver/Lib_AddressManager.sol";
 import { Lib_SecureMerkleTrie } from "../../../libraries/trie/Lib_SecureMerkleTrie.sol";
-import { Lib_ReentrancyGuard } from "../../../libraries/utils/Lib_ReentrancyGuard.sol";
 
 /* Interface Imports */
 import { iOVM_L1CrossDomainMessenger } from "../../../iOVM/bridge/messaging/iOVM_L1CrossDomainMessenger.sol";

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

@@ -4,7 +4,6 @@ pragma experimental ABIEncoderV2;
 
 /* Library Imports */
 import { Lib_AddressResolver } from "../../../libraries/resolver/Lib_AddressResolver.sol";
-import { Lib_ReentrancyGuard } from "../../../libraries/utils/Lib_ReentrancyGuard.sol";
 
 /* Interface Imports */
 import { iOVM_L2CrossDomainMessenger } from "../../../iOVM/bridge/messaging/iOVM_L2CrossDomainMessenger.sol";

packages/contracts/contracts/optimistic-ethereum/OVM/chain/OVM_CanonicalTransactionChain.sol

@@ -7,7 +7,6 @@ pragma experimental ABIEncoderV2;
 import { Lib_OVMCodec } from "../../libraries/codec/Lib_OVMCodec.sol";
 import { Lib_AddressResolver } from "../../libraries/resolver/Lib_AddressResolver.sol";
 import { Lib_MerkleTree } from "../../libraries/utils/Lib_MerkleTree.sol";
-import { Lib_Math } from "../../libraries/utils/Lib_Math.sol";
 
 /* Interface Imports */
 import { iOVM_CanonicalTransactionChain } from "../../iOVM/chain/iOVM_CanonicalTransactionChain.sol";
@@ -16,6 +15,9 @@ import { iOVM_ChainStorageContainer } from "../../iOVM/chain/iOVM_ChainStorageCo
 /* Contract Imports */
 import { OVM_ExecutionManager } from "../execution/OVM_ExecutionManager.sol";
 
+/* External Imports */
+import { Math } from "@openzeppelin/contracts/math/Math.sol";
+
 /**
  * @title OVM_CanonicalTransactionChain
  * @dev The Canonical Transaction Chain (CTC) contract is an append-only log of transactions
@@ -343,7 +345,7 @@ contract OVM_CanonicalTransactionChain is iOVM_CanonicalTransactionChain, Lib_Ad
         // TEMPORARY: Disable `appendQueueBatch` for minnet
         revert("appendQueueBatch is currently disabled.");
 
-        // _numQueuedTransactions = Lib_Math.min(_numQueuedTransactions, getNumPendingQueueElements());
+        // _numQueuedTransactions = Math.min(_numQueuedTransactions, getNumPendingQueueElements());
         // require(
         //     _numQueuedTransactions > 0,
         //     "Must append more than zero transactions."

packages/contracts/contracts/optimistic-ethereum/libraries/resolver/Lib_AddressManager.sol

 // SPDX-License-Identifier: MIT
 pragma solidity >0.5.0 <0.8.0;
 
-/* Contract Imports */
-import { Ownable } from "./Lib_Ownable.sol";
+/* External Imports */
+import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 
 /**
  * @title Lib_AddressManager

packages/contracts/contracts/optimistic-ethereum/libraries/resolver/Lib_Ownable.sol

-// SPDX-License-Identifier: MIT
-pragma solidity >0.5.0 <0.8.0;
-
-/**
- * @title Ownable
- * @dev Adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol
- */
-abstract contract Ownable {
-
-    /*************
-     * Variables *
-     *************/
-
-    address public owner;
-
-
-    /**********
-     * Events *
-     **********/
-
-    event OwnershipTransferred(
-        address indexed previousOwner,
-        address indexed newOwner
-    );
-
-
-    /***************
-     * Constructor *
-     ***************/
-
-    constructor() {
-        owner = msg.sender;
-        emit OwnershipTransferred(address(0), owner);
-    }
-
-
-    /**********************
-     * Function Modifiers *
-     **********************/
-
-    modifier onlyOwner() {
-        require(
-            owner == msg.sender,
-            "Ownable: caller is not the owner"
-        );
-        _;
-    }
-
-
-    /********************
-     * Public Functions *
-     ********************/
-
-    /**
-     * Sets the owner of this contract to the zero address, effectively renouncing ownership
-     * completely. Can only be called by the current owner of this contract.
-     */
-    function renounceOwnership()
-        public
-        virtual
-        onlyOwner
-    {
-        emit OwnershipTransferred(owner, address(0));
-        owner = address(0);
-    }
-
-    /**
-     * Transfers ownership of this contract to a new address. Can only be called by the current
-     * owner of this contract.
-     * @param _newOwner Address of the new contract owner.
-     */
-    function transferOwnership(
-        address _newOwner
-    )
-        public
-        virtual
-        onlyOwner
-    {
-        require(
-            _newOwner != address(0),
-            "Ownable: new owner cannot be the zero address"
-        );
-
-        emit OwnershipTransferred(owner, _newOwner);
-        owner = _newOwner;
-    }
-}

packages/contracts/contracts/optimistic-ethereum/libraries/utils/Lib_Math.sol

-// SPDX-License-Identifier: MIT
-pragma solidity >0.5.0 <0.8.0;
-
-/**
- * @title Lib_Math
- */
-library Lib_Math {
-
-    /**********************
-     * Internal Functions *
-     **********************/
-
-    /**
-     * Calculates the minumum of two numbers.
-     * @param _x First number to compare.
-     * @param _y Second number to compare.
-     * @return Lesser of the two numbers.
-     */
-    function min(
-        uint256 _x,
-        uint256 _y
-    )
-        internal
-        pure
-        returns (
-            uint256
-        )
-    {
-        if (_x < _y) {
-            return _x;
-        }
-
-        return _y;
-    }
-}

packages/contracts/contracts/optimistic-ethereum/libraries/utils/Lib_ReentrancyGuard.sol

-// SPDX-License-Identifier: MIT
-pragma solidity >0.5.0 <0.8.0;
-
-/**
- * @dev Contract module that helps prevent reentrant calls to a function.
- *
- * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
- * available, which can be applied to functions to make sure there are no nested
- * (reentrant) calls to them.
- *
- * Note that because there is a single `nonReentrant` guard, functions marked as
- * `nonReentrant` may not call one another. This can be worked around by making
- * those functions `private`, and then adding `external` `nonReentrant` entry
- * points to them.
- *
- * TIP: If you would like to learn more about reentrancy and alternative ways
- * to protect against it, check out our blog post
- * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
- */
-abstract contract Lib_ReentrancyGuard {
-    // Booleans are more expensive than uint256 or any type that takes up a full
-    // word because each write operation emits an extra SLOAD to first read the
-    // slot's contents, replace the bits taken up by the boolean, and then write
-    // back. This is the compiler's defense against contract upgrades and
-    // pointer aliasing, and it cannot be disabled.
-
-    // The values being non-zero value makes deployment a bit more expensive,
-    // but in exchange the refund on every call to nonReentrant will be lower in
-    // amount. Since refunds are capped to a percentage of the total
-    // transaction's gas, it is best to keep them low in cases like this one, to
-    // increase the likelihood of the full refund coming into effect.
-    uint256 private constant _NOT_ENTERED = 1;
-    uint256 private constant _ENTERED = 2;
-
-    uint256 private _status;
-
-    constructor () {
-        _status = _NOT_ENTERED;
-    }
-
-    /**
-     * @dev Prevents a contract from calling itself, directly or indirectly.
-     * Calling a `nonReentrant` function from another `nonReentrant`
-     * function is not supported. It is possible to prevent this from happening
-     * by making the `nonReentrant` function external, and make it call a
-     * `private` function that does the actual work.
-     */
-    modifier nonReentrant() {
-        // On the first call to nonReentrant, _notEntered will be true
-        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
-
-        // Any calls to nonReentrant after this point will fail
-        _status = _ENTERED;
-
-        _;
-
-        // By storing the original value once again, a refund is triggered (see
-        // https://eips.ethereum.org/EIPS/eip-2200)
-        _status = _NOT_ENTERED;
-    }
-}