Replace the usage of Magento\Framework\Json\DecoderInterface in the Bookmark model,

 - deprecate the $jsonDecoder,
 - inject the new \Magento\Framework\Serialize\Serializer\Json
 - replace the usage of $jsonDecoder with the $serializer

Author: dmanners

app/code/Magento/Ui/Model/Bookmark.php

@@ -23,9 +23,15 @@ class Bookmark extends AbstractExtensibleModel implements BookmarkInterface
 {
     /**
      * @var DecoderInterface
+     * @deprecated
      */
     protected $jsonDecoder;
 
+    /**
+     * @var \Magento\Framework\Serialize\Serializer\Json
+     */
+    private $serializer;
+
     /**
      * @param Context $context
      * @param Registry $registry
@@ -35,6 +41,8 @@ class Bookmark extends AbstractExtensibleModel implements BookmarkInterface
      * @param Collection $resourceCollection
      * @param DecoderInterface $jsonDecoder
      * @param array $data
+     * @param \Magento\Framework\Serialize\Serializer\Json|null $serializer
+     * @throws \RuntimeException
      */
     public function __construct(
         Context $context,
@@ -44,9 +52,12 @@ public function __construct(
         ResourceBookmark $resource,
         Collection $resourceCollection,
         DecoderInterface $jsonDecoder,
-        array $data = []
+        array $data = [],
+        \Magento\Framework\Serialize\Serializer\Json $serializer = null
     ) {
         $this->jsonDecoder = $jsonDecoder;
+        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
+            ->get(\Magento\Framework\Serialize\Serializer\Json::class);
         parent::__construct(
             $context,
             $registry,
@@ -127,7 +138,7 @@ public function getConfig()
     {
         $config = $this->getData(self::CONFIG);
         if ($config) {
-            return $this->jsonDecoder->decode($config);
+            return $this->serializer->unserialize($config);
         }
         return [];
     }