Added interface for LendingPoolLiquidationManager

contracts/interfaces/ILendingPoolCollateralManager.sol

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity 0.6.12;
+
+/**
+ * @title ILendingPoolCollateralManager interface
+ * @author Aave
+ * @notice Defines the actions involving management of collateral in the protocol.
+ **/
+interface ILendingPoolCollateralManager {
+  /**
+   * @dev emitted when a borrower is liquidated
+   * @param collateral the address of the collateral being liquidated
+   * @param principal the address of the reserve
+   * @param user the address of the user being liquidated
+   * @param debtToCover the total amount liquidated
+   * @param liquidatedCollateralAmount the amount of collateral being liquidated
+   * @param liquidator the address of the liquidator
+   * @param receiveAToken true if the liquidator wants to receive aTokens, false otherwise
+   **/
+  event LiquidationCall(
+    address indexed collateral,
+    address indexed principal,
+    address indexed user,
+    uint256 debtToCover,
+    uint256 liquidatedCollateralAmount,
+    address liquidator,
+    bool receiveAToken
+  );
+
+  /**
+   * @dev emitted when a user disables a reserve as collateral
+   * @param reserve the address of the reserve
+   * @param user the address of the user
+   **/
+  event ReserveUsedAsCollateralDisabled(address indexed reserve, address indexed user);
+
+  /**
+   * @dev users can invoke this function to liquidate an undercollateralized position.
+   * @param collateral the address of the collateral to liquidated
+   * @param principal the address of the principal reserve
+   * @param user the address of the borrower
+   * @param debtToCover the amount of principal that the liquidator wants to repay
+   * @param receiveAToken true if the liquidators wants to receive the aTokens, false if
+   * he wants to receive the underlying asset directly
+   **/
+  function liquidationCall(
+    address collateral,
+    address principal,
+    address user,
+    uint256 debtToCover,
+    bool receiveAToken
+  ) external virtual returns (uint256, string memory);
+}

contracts/protocol/lendingpool/LendingPool.sol

@@ -19,7 +19,6 @@ import {UserConfiguration} from '../libraries/configuration/UserConfiguration.so
 import {IStableDebtToken} from '../tokenization/interfaces/IStableDebtToken.sol';
 import {IVariableDebtToken} from '../tokenization/interfaces/IVariableDebtToken.sol';
 import {IFlashLoanReceiver} from '../../flashloan/interfaces/IFlashLoanReceiver.sol';
-import {LendingPoolCollateralManager} from './LendingPoolCollateralManager.sol'; // TODO change to interface
 import {IPriceOracleGetter} from '../../interfaces/IPriceOracleGetter.sol';
 import {SafeERC20} from '../../dependencies/openzeppelin/contracts/SafeERC20.sol';
 import {ILendingPool} from '../../interfaces/ILendingPool.sol';

contracts/protocol/lendingpool/LendingPoolCollateralManager.sol

@@ -8,6 +8,7 @@ import {IAToken} from '../tokenization/interfaces/IAToken.sol';
 import {IStableDebtToken} from '../tokenization/interfaces/IStableDebtToken.sol';
 import {IVariableDebtToken} from '../tokenization/interfaces/IVariableDebtToken.sol';
 import {IPriceOracleGetter} from '../../interfaces/IPriceOracleGetter.sol';
+import {ILendingPoolCollateralManager} from '../../interfaces/ILendingPoolCollateralManager.sol';
 import {GenericLogic} from '../libraries/logic/GenericLogic.sol';
 import {ReserveLogic} from '../libraries/logic/ReserveLogic.sol';
 import {UserConfiguration} from '../libraries/configuration/UserConfiguration.sol';
@@ -26,7 +27,7 @@ import {LendingPoolStorage} from './LendingPoolStorage.sol';
  * @notice this contract will be ran always through delegatecall
  * @dev LendingPoolCollateralManager inherits VersionedInitializable from OpenZeppelin to have the same storage layout as LendingPool
  **/
-contract LendingPoolCollateralManager is VersionedInitializable, LendingPoolStorage {
+contract LendingPoolCollateralManager is ILendingPoolCollateralManager, VersionedInitializable, LendingPoolStorage {
   using SafeERC20 for IERC20;
   using SafeMath for uint256;
   using WadRayMath for uint256;
@@ -37,33 +38,6 @@ contract LendingPoolCollateralManager is VersionedInitializable, LendingPoolStor
 
   uint256 internal constant LIQUIDATION_CLOSE_FACTOR_PERCENT = 5000;
 
-  /**
-   * @dev emitted when a borrower is liquidated
-   * @param collateral the address of the collateral being liquidated
-   * @param principal the address of the reserve
-   * @param user the address of the user being liquidated
-   * @param debtToCover the total amount liquidated
-   * @param liquidatedCollateralAmount the amount of collateral being liquidated
-   * @param liquidator the address of the liquidator
-   * @param receiveAToken true if the liquidator wants to receive aTokens, false otherwise
-   **/
-  event LiquidationCall(
-    address indexed collateral,
-    address indexed principal,
-    address indexed user,
-    uint256 debtToCover,
-    uint256 liquidatedCollateralAmount,
-    address liquidator,
-    bool receiveAToken
-  );
-
-  /**
-   * @dev emitted when a user disables a reserve as collateral
-   * @param reserve the address of the reserve
-   * @param user the address of the user
-   **/
-  event ReserveUsedAsCollateralDisabled(address indexed reserve, address indexed user);
-
   struct LiquidationCallLocalVars {
     uint256 userCollateralBalance;
     uint256 userStableDebt;
@@ -117,7 +91,7 @@ contract LendingPoolCollateralManager is VersionedInitializable, LendingPoolStor
     address user,
     uint256 debtToCover,
     bool receiveAToken
-  ) external returns (uint256, string memory) {
+  ) external override returns (uint256, string memory) {
     ReserveLogic.ReserveData storage collateralReserve = _reserves[collateral];
     ReserveLogic.ReserveData storage principalReserve = _reserves[principal];
     UserConfiguration.Map storage userConfig = _usersConfig[user];