MAGETWO-63910: Create infrastructure for mapper in Payment module

 - Refactored code according to code review.

Author: YevSent

app/code/Magento/Braintree/Model/AvsPaymentVerification.php renamed to app/code/Magento/Braintree/Model/AvsEmsCodeMapper.php

@@ -16,7 +16,7 @@
  * @see https://developers.braintreepayments.com/reference/response/transaction
  * @see http://www.emsecommerce.net/avs_cvv2_response_codes.htm
  */
-class AvsPaymentVerification implements PaymentVerificationInterface
+class AvsEmsCodeMapper implements PaymentVerificationInterface
 {
     /**
      * List of mapping AVS codes

app/code/Magento/Braintree/Model/CvvPaymentVerification.php renamed to app/code/Magento/Braintree/Model/CvvEmsMapper.php

@@ -16,7 +16,7 @@
  * @see https://developers.braintreepayments.com/reference/response/transaction
  * @see http://www.emsecommerce.net/avs_cvv2_response_codes.htm
  */
-class CvvPaymentVerification implements PaymentVerificationInterface
+class CvvEmsMapper implements PaymentVerificationInterface
 {
     /**
      * List of mapping CVV codes

app/code/Magento/Braintree/etc/config.xml

@@ -40,8 +40,8 @@
                 <masked_fields>cvv,number</masked_fields>
                 <privateInfoKeys>avsPostalCodeResponseCode,avsStreetAddressResponseCode,cvvResponseCode,processorAuthorizationCode,processorResponseCode,processorResponseText,liabilityShifted,liabilityShiftPossible,riskDataId,riskDataDecision</privateInfoKeys>
                 <paymentInfoKeys>cc_type,cc_number,avsPostalCodeResponseCode,avsStreetAddressResponseCode,cvvResponseCode,processorAuthorizationCode,processorResponseCode,processorResponseText,liabilityShifted,liabilityShiftPossible,riskDataId,riskDataDecision</paymentInfoKeys>
-                <avs_ems_adapter>Magento\Braintree\Model\AvsPaymentVerification</avs_ems_adapter>
-                <cvv_ems_adapter>Magento\Braintree\Model\CvvPaymentVerification</cvv_ems_adapter>
+                <avs_ems_adapter>Magento\Braintree\Model\AvsEmsCodeMapper</avs_ems_adapter>
+                <cvv_ems_adapter>Magento\Braintree\Model\CvvEmsMapper</cvv_ems_adapter>
             </braintree>
             <braintree_paypal>
                 <model>BraintreePayPalFacade</model>

app/code/Magento/Payment/Api/PaymentVerificationInterface.php

@@ -10,15 +10,21 @@
 /**
  * Payment provider codes verification interface.
  *
+ * Custom payment methods might implement this interface to provide
+ * specific mapping for payment methods, like AVS or CVV verification.
+ * The payment methods can map payment method info from internal sources,
+ * like additional information, to specific international codes.
+ *
  * @api
  */
 interface PaymentVerificationInterface
 {
     /**
      * Gets payment provider verification code.
-     * Returns null if payment method does not support verification.
+     * Returns null if verification cannot be obtained by payment method.
      *
-     * @return string|null
+     * @param OrderPaymentInterface $orderPayment
+     * @return string
      */
     public function getCode(OrderPaymentInterface $orderPayment);
 }