Clean up of UtilityToken and UtilityTokenInterface.

contracts/gateway/CoGatewayUtilityTokenInterface.sol

@@ -15,7 +15,6 @@ pragma solidity ^0.5.0;
 // limitations under the License.
 //
 // ----------------------------------------------------------------------------
-// Auxiliary Chain: CoGatewayUtilityTokenInterface
 //
 // http://www.simpletoken.org/
 //
@@ -30,5 +29,5 @@ contract CoGatewayUtilityTokenInterface {
      */
     function utilityToken()
         public
-        returns (address);
+        returns (address utilityToken_);
 }

contracts/gateway/EIP20CoGateway.sol

@@ -1110,10 +1110,10 @@ contract EIP20CoGateway is GatewayBase {
         mintedAmount_ = stakeAmount_.sub(rewardAmount_);
 
         //Mint token after subtracting reward amount
-        UtilityTokenInterface(utilityToken).mint(beneficiary_, mintedAmount_);
+        UtilityTokenInterface(utilityToken).increaseSupply(beneficiary_, mintedAmount_);
 
         //reward beneficiary with the reward amount
-        UtilityTokenInterface(utilityToken).mint(msg.sender, rewardAmount_);
+        UtilityTokenInterface(utilityToken).increaseSupply(msg.sender, rewardAmount_);
 
         // delete the mint data
         delete mints[_messageHash];
@@ -1160,7 +1160,7 @@ contract EIP20CoGateway is GatewayBase {
         redeemer_ = message.sender;
         redeemAmount_ = redeems[_messageHash].amount;
         // Burn the redeem amount.
-        UtilityTokenInterface(utilityToken).burn(redeemAmount_);
+        UtilityTokenInterface(utilityToken).decreaseSupply(redeemAmount_);
 
         // Transfer the bounty amount to the facilitator
         msg.sender.transfer(redeems[_messageHash].bounty);

contracts/gateway/OSTPrime.sol

@@ -31,7 +31,7 @@ pragma solidity ^0.5.0;
 import "../lib/SafeMath.sol";
 import "./UtilityToken.sol";
 import "./OSTPrimeConfig.sol";
-
+import "../lib/IsMemberInterface.sol";
 
 /**
  *  @title OSTPrime contract implements UtilityToken and
@@ -92,14 +92,19 @@ contract OSTPrime is UtilityToken, OSTPrimeConfig {
      * @dev This contract should be deployed with zero gas.
      *
      * @param _valueToken ERC20 token address in origin chain.
+     * @param _membersManager Address of a contract that manages organization.
      */
-    constructor(address _valueToken)
+    constructor(
+        EIP20Interface _valueToken,
+        IsMemberInterface _membersManager
+    )
         public
         UtilityToken(
+            _valueToken,
             TOKEN_SYMBOL,
             TOKEN_NAME,
             TOKEN_DECIMALS,
-            _valueToken
+            _membersManager
         )
     {}
 
@@ -212,4 +217,47 @@ contract OSTPrime is UtilityToken, OSTPrimeConfig {
         success_ = true;
     }
 
+    /**
+     * @notice Adds number of OST Prime tokens to account balance and increases
+     *         the total token supply. Can be called only when contract is
+     *         initialized and only by CoGateway address.
+     *
+     * @param _account Account address for which the OST Prime balance will be
+     *                 increased.
+     * @param _amount Amount of tokens.
+     *
+     * @return success_ `true` if increase supply is successful, false otherwise.
+     */
+    function increaseSupply(
+        address _account,
+        uint256 _amount
+    )
+        external
+        onlyInitialized
+        onlyCoGateway
+        returns (bool success_)
+    {
+        success_ = increaseSupplyInternal(_account, _amount);
+    }
+
+    /**
+     * @notice Decreases the OST Prime token balance from the msg.sender
+     *         address and decreases the total token supply count. Can be
+     *         called only when contract is initialized and only by CoGateway
+     *         address.
+     *
+     * @param _amount Amount of tokens.
+     *
+     * @return success_ `true` if decrease supply is successful, false otherwise.
+     */
+    function decreaseSupply(
+        uint256 _amount
+    )
+        external
+        onlyInitialized
+        onlyCoGateway
+        returns (bool success_)
+    {
+        success_ = decreaseSupplyInternal(_amount);
+    }
 }