MAGETWO-90652: PayPal BrainTree order fails to checkout with 500 Error

Author: Joan He

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

@@ -447,7 +447,7 @@
     <!-- PayPal value handlers infrastructure -->
     <type name="Magento\Braintree\Gateway\Response\PayPal\VaultDetailsHandler">
         <arguments>
-            <argument name="paymentTokenFactory" xsi:type="object">Magento\Vault\Model\AccountPaymentTokenFactory</argument>
+            <argument name="paymentTokenFactory" xsi:type="object">Magento\Vault\Api\Data\PaymentTokenFactoryInterface</argument>
         </arguments>
     </type>
     <virtualType name="BraintreePayPalValueHandlerPool" type="Magento\Payment\Gateway\Config\ValueHandlerPool">

app/code/Magento/Vault/Model/PaymentTokenFactory.php

@@ -22,6 +22,11 @@ class PaymentTokenFactory implements PaymentTokenFactoryInterface
      */
     private $tokenTypes = [];
 
+    /**
+     * @var ObjectManagerInterface
+     */
+    private $objectManager;
+
     /**
      * PaymentTokenFactory constructor.
      * @param ObjectManagerInterface $objectManager