[Serializer] Remove AbstractObjectNormalizer::isAttributeToNormalize

UPGRADE-3.1.md

@@ -111,6 +111,10 @@ Serializer
    deprecated and will not be supported in Symfony 4.0. You should use the
    `CacheClassMetadataFactory` class instead.
 
+ * The `AbstractObjectNormalizer::isAttributeToNormalize()` method has been removed
+   because it was initially added by mistake, has never been used and is not tested
+   nor documented.
+
 Translation
 -----------
 

src/Symfony/Component/Serializer/Normalizer/AbstractObjectNormalizer.php

@@ -208,20 +208,6 @@ abstract class AbstractObjectNormalizer extends AbstractNormalizer
      */
     abstract protected function setAttributeValue($object, $attribute, $value, $format = null, array $context = array());
 
-    /**
-     * Should this attribute be normalized?
-     *
-     * @param mixed  $object
-     * @param string $attributeName
-     * @param array  $context
-     *
-     * @return bool
-     */
-    protected function isAttributeToNormalize($object, $attributeName, &$context)
-    {
-        return !in_array($attributeName, $this->ignoredAttributes) && !$this->isMaxDepthReached(get_class($object), $attributeName, $context);
-    }
-
     /**
      * Validates the submitted data and denormalizes it.
      *