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/
 //
@@ -26,9 +25,9 @@ contract CoGatewayUtilityTokenInterface {
     /**
      * @notice Get the utility token address.
      *
-     * @return address of utility token.
+     * @return utilityToken_ Address of utility token.
      */
     function utilityToken()
         public
-        returns (address);
+        returns (address utilityToken_);
 }

contracts/gateway/EIP20CoGateway.sol

@@ -1061,12 +1061,12 @@ contract EIP20CoGateway is GatewayBase {
      * @notice This is internal method for process minting contains common logic.
      *
      * @param _messageHash Message hash.
-     * @param _initialGas initial gas during progress process.
+     * @param _initialGas Initial gas during progress process.
      *
-     * @param _proofProgress true if progress with proof, false if progress
+     * @param _proofProgress `true` if progress with proof, false if progress
      *                       with hashlock.
-     * @param _unlockSecret unlock secret to progress, zero in case of progress
-     *                      with proof
+     * @param _unlockSecret Unlock secret to progress, zero in case of progress
+     *                      with proof.
      *
      * @return  beneficiary_ Address to which the utility tokens will be
      *                      transferred after minting.
@@ -1075,7 +1075,7 @@ contract EIP20CoGateway is GatewayBase {
      *                      is given to the facilitator.
      * @return mintedAmount_ Actual minted amount, after deducting the reward
      *                        from the total amount.
-     * @return rewardAmount_ Reward amount that is transferred to facilitator
+     * @return rewardAmount_ Reward amount that is transferred to facilitator.
      */
 
     function progressMintInternal(
@@ -1109,16 +1109,22 @@ contract EIP20CoGateway is GatewayBase {
 
         mintedAmount_ = stakeAmount_.sub(rewardAmount_);
 
-        //Mint token after subtracting reward amount
-        UtilityTokenInterface(utilityToken).mint(beneficiary_, mintedAmount_);
+        // Mint token after subtracting reward amount.
+        UtilityTokenInterface(utilityToken).increaseSupply(
+            beneficiary_,
+            mintedAmount_
+        );
 
-        //reward beneficiary with the reward amount
-        UtilityTokenInterface(utilityToken).mint(msg.sender, rewardAmount_);
+        // Reward beneficiary with the reward amount.
+        UtilityTokenInterface(utilityToken).increaseSupply(
+            msg.sender,
+            rewardAmount_
+        );
 
-        // delete the mint data
+        // Delete the mint data.
         delete mints[_messageHash];
 
-        // Emit MintProgressed event
+        // Emit MintProgressed event.
         emit MintProgressed(
             _messageHash,
             message.sender,
@@ -1136,13 +1142,13 @@ contract EIP20CoGateway is GatewayBase {
      * @notice Internal method to progressRedeemInternal.
      *
      * @param _messageHash Message hash.
-     * @param _proofProgress true if progress with proof, false if progress
+     * @param _proofProgress True if progress with proof, false if progress
      *                       with hashlock.
-     * @param _unlockSecret unlock secret to progress, zero in case of progress
-     *                      with proof
+     * @param _unlockSecret Unlock secret to progress, zero in case of progress
+     *                      with proof.
      *
-     * @return redeemer_ Redeemer address
-     * @return redeemAmount_ Redeem amount
+     * @return redeemer_ Redeemer address.
+     * @return redeemAmount_ Redeem amount.
      */
     function progressRedeemInternal(
         bytes32 _messageHash,
@@ -1159,13 +1165,14 @@ contract EIP20CoGateway is GatewayBase {
 
         redeemer_ = message.sender;
         redeemAmount_ = redeems[_messageHash].amount;
-        // Burn the redeem amount.
-        UtilityTokenInterface(utilityToken).burn(redeemAmount_);
 
-        // Transfer the bounty amount to the facilitator
+        // Decrease the token supply.
+        UtilityTokenInterface(utilityToken).decreaseSupply(redeemAmount_);
+
+        // Transfer the bounty amount to the facilitator.
         msg.sender.transfer(redeems[_messageHash].bounty);
 
-        // delete the redeem data
+        // Delete the redeem data.
         delete redeems[_messageHash];
 
         // Emit RedeemProgressed event.

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 +217,53 @@ 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.
+     *
+     * @dev The parameters _account and _amount should not be zero. This check
+     *      is added in function increaseSupplyInternal.
+     *
+     * @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.
+     *
+     * @dev The parameters _amount should not be zero. This check is added in
+     *      function decreaseSupplyInternal.
+     *
+     * @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);
+    }
 }