Renamed MixinFees -> MixinExchangeFees

contracts/staking/contracts/src/Staking.sol

@@ -26,7 +26,7 @@ import "./core/MixinScheduler.sol";
 import "./core/MixinStakeBalances.sol";
 import "./core/MixinStake.sol";
 import "./core/MixinPools.sol";
-import "./core/MixinFees.sol";
+import "./core/MixinExchangeFees.sol";
 import "./core/MixinRewards.sol";
 
 
@@ -43,7 +43,7 @@ contract Staking is
     MixinPools,
     MixinRewards,
     MixinStake,
-    MixinFees
+    MixinExchangeFees
 {
 
     // this contract can receive ETH

contracts/staking/contracts/src/core/MixinExchangeFees.sol

@@ -31,7 +31,7 @@ import "./MixinRewardVault.sol";
 import "../interfaces/IStructs.sol";
 
 
-contract MixinFees is
+contract MixinExchangeFees is
     IStakingEvents,
     MixinConstants,
     MixinStorage,

contracts/staking/contracts/src/core/MixinOwnable.sol

@@ -0,0 +1,40 @@
+pragma solidity ^0.5.9;
+
+import "../interfaces/IStakingEvents.sol";
+import "../immutable/MixinStorage.sol";
+
+
+contract MixinOwnable is
+    IStakingEvents,
+    MixinStorage
+{
+
+    /// @dev This mixin contains logic for ownable contracts.
+    /// Note that unlike the standardized `ownable` contract,
+    /// there is no state declared here. It is instead located
+    /// in `immutable/MixinStorage.sol` and its value is set
+    /// by the delegating proxy (StakingProxy.sol)
+
+    /// @dev reverts if called by a sender other than the owner.
+    modifier onlyOwner() {
+        require(
+            msg.sender == owner,
+            "NOT_OWNER"
+        );
+        _;
+    }
+
+    /// @dev Transfers the ownership of this contract
+    /// @param newOwner New owner of contract
+    function transferOwnership(address newOwner)
+        external
+        onlyOwner
+    {
+        require(
+            newOwner != address(0),
+            "CANNOT_SET_OWNEROT_ADDRESS_ZERO"
+        );
+        owner = newOwner;
+        emit OwnershipTransferred(newOwner);
+    }
+}

contracts/staking/contracts/src/interfaces/IStakingEvents.sol

@@ -47,7 +47,7 @@ interface IStakingEvents {
         uint64 endEpoch
     );
 
-    /// @dev Emitted by MixinFees when rewards are paid out.
+    /// @dev Emitted by MixinExchangeFees when rewards are paid out.
     /// @param totalActivePools Total active pools this epoch.
     /// @param totalFeesCollected Total fees collected this epoch, across all active pools.
     /// @param totalWeightedStake Total weighted stake attributed to each pool. Delegated stake is weighted less.
@@ -68,4 +68,4 @@ interface IStakingEvents {
     event OwnershipTransferred(
         address newOwner
     );
-}
+}