Make sure that the new dependancy on SerializerInterface is not required

Author: dmanners

app/code/Magento/Captcha/Controller/Adminhtml/Refresh/Refresh.php

@@ -22,16 +22,18 @@ class Refresh extends \Magento\Backend\App\Action
 
     /**
      * @param \Magento\Backend\App\Action\Context $context
-     * @param \Magento\Framework\Serialize\SerializerInterface $serializer
+     * @param \Magento\Framework\Serialize\SerializerInterface|null $serializer
      * @param \Magento\Captcha\Helper\Data $captchaHelper
+     * @throws \RuntimeException
      */
     public function __construct(
         \Magento\Backend\App\Action\Context $context,
-        \Magento\Framework\Serialize\SerializerInterface $serializer,
+        \Magento\Framework\Serialize\SerializerInterface $serializer = null,
         \Magento\Captcha\Helper\Data $captchaHelper
     ) {
         parent::__construct($context);
-        $this->serializer = $serializer;
+        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
+            ->get(\Magento\Framework\Serialize\SerializerInterface::class);
         $this->captchaHelper = $captchaHelper;
     }
 

app/code/Magento/Captcha/Controller/Refresh/Index.php

@@ -25,15 +25,17 @@ class Index extends \Magento\Framework\App\Action\Action
     /**
      * @param Context $context
      * @param \Magento\Captcha\Helper\Data $captchaHelper
-     * @param \Magento\Framework\Serialize\SerializerInterface $serializer
+     * @param \Magento\Framework\Serialize\SerializerInterface|null $serializer
+     * @throws \RuntimeException
      */
     public function __construct(
         Context $context,
         \Magento\Captcha\Helper\Data $captchaHelper,
-        \Magento\Framework\Serialize\SerializerInterface $serializer
+        \Magento\Framework\Serialize\SerializerInterface $serializer = null
     ) {
         $this->captchaHelper = $captchaHelper;
-        $this->serializer = $serializer;
+        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
+            ->get(\Magento\Framework\Serialize\SerializerInterface::class);
         parent::__construct($context);
     }
 

app/code/Magento/Captcha/Model/Customer/Plugin/AjaxLogin.php

@@ -40,20 +40,22 @@ class AjaxLogin
      * @param CaptchaHelper $helper
      * @param SessionManagerInterface $sessionManager
      * @param JsonFactory $resultJsonFactory
-     * @param \Magento\Framework\Serialize\SerializerInterface $serializer
+     * @param \Magento\Framework\Serialize\SerializerInterface|null $serializer
      * @param array $formIds
+     * @throws \RuntimeException
      */
     public function __construct(
         CaptchaHelper $helper,
         SessionManagerInterface $sessionManager,
         JsonFactory $resultJsonFactory,
-        \Magento\Framework\Serialize\SerializerInterface $serializer,
+        \Magento\Framework\Serialize\SerializerInterface $serializer = null,
         array $formIds
     ) {
         $this->helper = $helper;
         $this->sessionManager = $sessionManager;
         $this->resultJsonFactory = $resultJsonFactory;
-        $this->serializer = $serializer;
+        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
+            ->get(\Magento\Framework\Serialize\SerializerInterface::class);
         $this->formIds = $formIds;
     }