diff --git a/core/core.services.yml b/core/core.services.yml
index 4e1b13b..b3b0228 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -39,7 +39,7 @@ services:
     tags:
       - { name: service_collector, call: addInvalidator }
   cache_tags.checksum:
-    class: Drupal\Core\Cache\DatabaseCacheTagsStorage
+    class: Drupal\Core\Cache\DatabaseCacheTagsChecksum
     arguments: ['@database']
     tags:
       - { name: cache_tags_invalidator}
diff --git a/core/lib/Drupal/Core/Cache/DatabaseCacheTagsChecksum.php b/core/lib/Drupal/Core/Cache/DatabaseCacheTagsChecksum.php
index 0a519f4..784294e 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseCacheTagsChecksum.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseCacheTagsChecksum.php
@@ -11,7 +11,7 @@
 use Drupal\Core\Database\SchemaObjectExistsException;
 
 /**
- * Storage for cache tag invalidations.
+ * Cache tags invalidations checksum implementation that uses the database.
  */
 class DatabaseCacheTagsChecksum implements CacheTagsChecksumInterface, CacheTagsInvalidatorInterface {
 
@@ -81,6 +81,25 @@ public function invalidateTags(array $tags) {
    * {@inheritdoc}
    */
   public function getCurrentChecksum(array $tags) {
+    // Remove tags that were already invalidated during this request from the
+    // static caches so that another deletion or invalidation can occur.
+    foreach ($tags as $tag) {
+      unset($this->invalidatedTags[$tag]);
+    }
+    return $this->calculateChecksum($tags);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isValid($checksum, array $tags) {
+    return $checksum == $this->calculateChecksum($tags);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function calculateChecksum(array $tags) {
     $checksum = 0;
 
     $query_tags = array_diff($tags, array_keys($this->tagCache));
@@ -111,17 +130,6 @@ public function getCurrentChecksum(array $tags) {
   /**
    * {@inheritdoc}
    */
-  public function onCacheTagsWrite(array $tags) {
-    // Remove tags that were already invalidated during this request from the
-    // static caches so that another deletion or invalidation can occur.
-    foreach ($tags as $tag) {
-      unset($this->invalidatedTags[$tag]);
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function reset() {
     $this->tagCache = array();
     $this->invalidatedTags = array();