Added delegation capabilities to the aToken

contracts/interfaces/ILendingPool.sol

@@ -4,6 +4,7 @@ pragma solidity ^0.6.8;
 import {ReserveConfiguration} from '../libraries/configuration/ReserveConfiguration.sol';
 import {UserConfiguration} from '../libraries/configuration/UserConfiguration.sol';
 import {ReserveLogic} from '../libraries/logic/ReserveLogic.sol';
+import {ILendingPoolAddressesProvider} from './ILendingPoolAddressesProvider.sol';
 
 pragma experimental ABIEncoderV2;
 
@@ -368,6 +369,8 @@ interface ILendingPool {
 
   function getReservesList() external view returns (address[] memory);
 
+  function getAddressesProvider() external view returns (ILendingPoolAddressesProvider);
+
   /**
    * @dev Set the _pause state
    * @param val the boolean value to set the current pause state of LendingPool

contracts/lendingpool/LendingPool.sol

@@ -753,7 +753,7 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage
   /**
    * @dev returns the addresses provider
    **/
-  function getAddressesProvider() external view returns (ILendingPoolAddressesProvider) {
+  function getAddressesProvider() external override view returns (ILendingPoolAddressesProvider) {
     return _addressesProvider;
   }
 

contracts/lendingpool/LendingPoolConfigurator.sol

@@ -188,10 +188,10 @@ contract LendingPoolConfigurator is VersionedInitializable {
   ILendingPool internal pool;
 
   /**
-   * @dev only the lending pool manager can call functions affected by this modifier
+   * @dev only the aave admin can call functions affected by this modifier
    **/
   modifier onlyAaveAdmin {
-    require(addressesProvider.getAaveAdmin() == msg.sender, Errors.LPC_CALLER_NOT_AAVE_ADMIN);
+    require(addressesProvider.getAaveAdmin() == msg.sender, Errors.CALLER_NOT_AAVE_ADMIN);
     _;
   }
 

contracts/libraries/helpers/Errors.sol

@@ -17,6 +17,10 @@ pragma solidity ^0.6.8;
  *  - P = Pausable
  */
 library Errors {
+  //common errors
+  string public constant CALLER_NOT_AAVE_ADMIN = '33'; // 'The caller must be the aave admin'
+
+  //contract specific errors
   string public constant VL_AMOUNT_NOT_GREATER_THAN_0 = '1'; // 'Amount must be greater than 0'
   string public constant VL_NO_ACTIVE_RESERVE = '2'; // 'Action requires an active reserve'
   string public constant VL_RESERVE_FROZEN = '3'; // 'Action cannot be performed because the reserve is frozen'
@@ -49,7 +53,6 @@ library Errors {
   string public constant AT_CANNOT_GIVE_ALLVWANCE_TO_HIMSELF = '30'; // 'User cannot give allowance to himself'
   string public constant AT_TRANSFER_AMOUNT_NOT_GT_0 = '31'; // 'Transferred amount needs to be greater than zero'
   string public constant RL_RESERVE_ALREADY_INITIALIZED = '32'; // 'Reserve has already been initialized'
-  string public constant LPC_CALLER_NOT_AAVE_ADMIN = '33'; // 'The caller must be the aave admin'
   string public constant LPC_RESERVE_LIQUIDITY_NOT_0 = '34'; // 'The liquidity of the reserve needs to be 0'
   string public constant LPC_INVALID_ATOKEN_POOL_ADDRESS = '35'; // 'The liquidity of the reserve needs to be 0'
   string public constant LPC_INVALID_STABLE_DEBT_TOKEN_POOL_ADDRESS = '36'; // 'The liquidity of the reserve needs to be 0'

contracts/tokenization/DelegationAwareAToken.sol

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: agpl-3.0
+pragma solidity ^0.6.8;
+
+import {AToken} from './AToken.sol';
+import {ILendingPool} from '../interfaces/ILendingPool.sol';
+import {Errors} from '../libraries/helpers/Errors.sol';
+
+/**
+ * @title IDelegationToken
+ * @dev implements an interface for tokens that have a delegation function
+ **/
+interface IDelegationToken {
+  function delegate(address delegatee) external;
+}
+
+/**
+ * @title Aave AToken with delegation capabilities
+ *
+ * @dev Implementation of the interest bearing token for the Aave protocol. This version of the aToken
+ * adds a function which gives the Aave protocol the ability to delegate voting power of underlying assets
+ * that are compatible with the Compound delegation interface
+ * @author Aave
+ */
+contract DelegationAwareAToken is AToken {
+  /**
+   * @dev only the aave admin can call this function
+   **/
+  modifier onlyAaveAdmin {
+    require(
+      _msgSender() == ILendingPool(POOL).getAddressesProvider().getAaveAdmin(),
+      Errors.CALLER_NOT_AAVE_ADMIN
+    );
+    _;
+  }
+
+  constructor(
+    ILendingPool pool,
+    address underlyingAssetAddress,
+    address reserveTreasury,
+    string memory tokenName,
+    string memory tokenSymbol,
+    address incentivesController
+  )
+    public
+    AToken(
+      pool,
+      underlyingAssetAddress,
+      reserveTreasury,
+      tokenName,
+      tokenSymbol,
+      incentivesController
+    )
+  {}
+
+  function getRevision() internal override pure returns (uint256) {
+    return 0x1;
+  }
+
+  function initialize(
+    uint8 _underlyingAssetDecimals,
+    string calldata _tokenName,
+    string calldata _tokenSymbol
+  ) external virtual override initializer {
+    _setName(_tokenName);
+    _setSymbol(_tokenSymbol);
+    _setDecimals(_underlyingAssetDecimals);
+  }
+
+  /**
+   * @dev delegates voting power of the underlying asset to a specific address
+   * @param delegatee the address that will receive the delegation
+   **/
+  function delegateUnderlyingTo(address delegatee) external onlyAaveAdmin {
+    IDelegationToken(UNDERLYING_ASSET_ADDRESS).delegate(delegatee);
+  }
+}