diff --git a/core/lib/Drupal/Core/Cache/ApcuBackend.php b/core/lib/Drupal/Core/Cache/ApcuBackend.php
index d7bdbdb..e5e9f64 100644
--- a/core/lib/Drupal/Core/Cache/ApcuBackend.php
+++ b/core/lib/Drupal/Core/Cache/ApcuBackend.php
@@ -163,13 +163,12 @@ protected function prepareItem($cache, $allow_invalid) {
     }
 
     $cache->tags = $cache->tags ? explode(' ', $cache->tags) : array();
-    $checksum = $this->cacheTagsStorage->checksumTags($cache->tags);
 
     // Check expire time.
     $cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
 
     // Check if invalidateTags() has been called with any of the entry's tags.
-    if ($cache->checksum_invalidations != $checksum) {
+    if ($cache->checksum != $this->cacheTagsStorage->checksumTags($cache->tags)) {
       $cache->valid = FALSE;
     }
 
@@ -185,18 +184,17 @@ protected function prepareItem($cache, $allow_invalid) {
    */
   public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = array()) {
     if ($tags) {
+      $tags = array_unique($tags);
       Cache::validateTags($tags);
       $this->cacheTagsStorage->onCacheTagsWrite($tags);
     }
 
-    $tags = array_unique($tags);
     $cache = new \stdClass();
     $cache->cid = $cid;
     $cache->created = round(microtime(TRUE), 3);
     $cache->expire = $expire;
     $cache->tags = implode(' ', $tags);
-    $checksum = $this->cacheTagsStorage->checksumTags($tags);
-    $cache->checksum_invalidations = $checksum;
+    $cache->checksum = $this->cacheTagsStorage->checksumTags($tags);;
     // APC serializes/unserializes any structure itself.
     $cache->serialized = 0;
     $cache->data = $data;
diff --git a/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php b/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
index 543d195..636ce77 100644
--- a/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
+++ b/core/lib/Drupal/Core/Cache/CacheTagsInvalidator.php
@@ -55,8 +55,8 @@ public function addInvalidator(CacheTagsInvalidatorInterface $invalidator) {
    * Returns all cache bins that need to be notified about invalidations.
    *
    * @return \Drupal\Core\Cache\CacheTagsInvalidatorInterface[]
-   *   An array of cache backend objects that implement the invalidator interface,
-   *   keyed by their cache bin.
+   *   An array of cache backend objects that implement the invalidator
+   *   interface, keyed by their cache bin.
    */
   protected function getInvalidatorCacheBins() {
     $bins = array();
diff --git a/core/lib/Drupal/Core/Cache/DatabaseBackend.php b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
index 10445e4..5e90a75 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseBackend.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseBackend.php
@@ -86,7 +86,7 @@ public function getMultiple(&$cids, $allow_invalid = FALSE) {
     // ::select() is a much smaller proportion of the request.
     $result = array();
     try {
-      $result = $this->connection->query('SELECT cid, data, created, expire, serialized, tags, checksum_invalidations FROM {' . $this->connection->escapeTable($this->bin) . '} WHERE cid IN (:cids)', array(':cids' => array_keys($cid_mapping)));
+      $result = $this->connection->query('SELECT cid, data, created, expire, serialized, tags, checksum FROM {' . $this->connection->escapeTable($this->bin) . '} WHERE cid IN (:cids)', array(':cids' => array_keys($cid_mapping)));
     }
     catch (\Exception $e) {
       // Nothing to do.
@@ -126,13 +126,11 @@ protected function prepareItem($cache, $allow_invalid) {
 
     $cache->tags = $cache->tags ? explode(' ', $cache->tags) : array();
 
-    $checksum = $this->cacheTagStorage->checksumTags($cache->tags);
-
     // Check expire time.
     $cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
 
     // Check if invalidateTags() has been called with any of the entry's tags.
-    if ($cache->checksum_invalidations != $checksum) {
+    if ($cache->checksum != $this->cacheTagStorage->checksumTags($cache->tags)) {
       $cache->valid = FALSE;
     }
 
@@ -182,13 +180,11 @@ public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = array
    * Actually set the cache.
    */
   protected function doSet($cid, $data, $expire, $tags) {
-    $checksum = $this->cacheTagStorage->checksumTags($tags);
     $fields = array(
-      'serialized' => 0,
       'created' => round(microtime(TRUE), 3),
       'expire' => $expire,
       'tags' => implode(' ', $tags),
-      'checksum_invalidations' => $checksum,
+      'checksum' => $this->cacheTagStorage->checksumTags($tags),
     );
     if (!is_string($data)) {
       $fields['data'] = serialize($data);
@@ -220,7 +216,7 @@ public function setMultiple(array $items) {
 
       $query = $this->connection
         ->insert($this->bin)
-        ->fields(array('cid', 'data', 'expire', 'created', 'serialized', 'tags', 'checksum_invalidations'));
+        ->fields(array('cid', 'data', 'expire', 'created', 'serialized', 'tags', 'checksum'));
 
       foreach ($items as $cid => $item) {
         $item += array(
@@ -235,14 +231,13 @@ public function setMultiple(array $items) {
           sort($item['tags']);
           $this->cacheTagStorage->onCacheTagsWrite($item['tags']);
         }
-        $checksum = $this->cacheTagStorage->checksumTags($item['tags']);
 
         $fields = array(
           'cid' => $cid,
           'expire' => $item['expire'],
           'created' => round(microtime(TRUE), 3),
           'tags' => implode(' ', $item['tags']),
-          'checksum_invalidations' => $checksum,
+          'checksum' => $this->cacheTagStorage->checksumTags($item['tags']),
         );
 
         if (!is_string($item['data'])) {
@@ -491,7 +486,7 @@ public function schemaDefinition() {
           'size' => 'big',
           'not null' => FALSE,
         ),
-        'checksum_invalidations' => array(
+        'checksum' => array(
           'description' => 'The tag invalidation sum when this entry was saved.',
           'type' => 'int',
           'not null' => TRUE,
diff --git a/core/lib/Drupal/Core/Cache/DatabaseCacheTagsStorage.php b/core/lib/Drupal/Core/Cache/DatabaseCacheTagsStorage.php
index db4363a..b8c0556 100644
--- a/core/lib/Drupal/Core/Cache/DatabaseCacheTagsStorage.php
+++ b/core/lib/Drupal/Core/Cache/DatabaseCacheTagsStorage.php
@@ -81,7 +81,7 @@ public function invalidateTags(array $tags) {
    * {@inheritdoc}
    */
   public function checksumTags(array $tags) {
-    $invalidations = 0;
+    $checksum = 0;
 
     $query_tags = array_diff($tags, array_keys($this->tagCache));
     if ($query_tags) {
@@ -102,10 +102,10 @@ public function checksumTags(array $tags) {
     }
 
     foreach ($tags as $tag) {
-      $invalidations += $this->tagCache[$tag];
+      $checksum += $this->tagCache[$tag];
     }
 
-    return $invalidations;
+    return $checksum;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Cache/PhpBackend.php b/core/lib/Drupal/Core/Cache/PhpBackend.php
index ce120b9..99e7598 100644
--- a/core/lib/Drupal/Core/Cache/PhpBackend.php
+++ b/core/lib/Drupal/Core/Cache/PhpBackend.php
@@ -133,8 +133,7 @@ protected function prepareItem($cache, $allow_invalid) {
     $cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
 
     // Check if invalidateTags() has been called with any of the item's tags.
-    $checksum = $this->cacheTagsStorage->checksumTags($cache->tags);
-    if ($cache->checksum_invalidations != $checksum) {
+    if ($cache->checksum != $this->cacheTagsStorage->checksumTags($cache->tags)) {
       $cache->valid = FALSE;
     }
 
@@ -150,6 +149,7 @@ protected function prepareItem($cache, $allow_invalid) {
    */
   public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = array()) {
     if ($tags) {
+      $tags = array_unique($tags);
       Cache::validateTags($tags);
       $this->cacheTagsStorage->onCacheTagsWrite($tags);
     }
@@ -158,8 +158,8 @@ public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = array
       'data' => $data,
       'created' => round(microtime(TRUE), 3),
       'expire' => $expire,
-      'tags' => array_unique($tags),
-      'checksum_invalidations' => $this->cacheTagsStorage->checksumTags($tags),
+      'tags' => $tags,
+      'checksum' => $this->cacheTagsStorage->checksumTags($tags),
     );
     $this->writeItem($this->normalizeCid($cid), $item);
   }
diff --git a/core/modules/field/src/Entity/FieldStorageConfig.php b/core/modules/field/src/Entity/FieldStorageConfig.php
index a82f2ba..9ae0fc4 100644
--- a/core/modules/field/src/Entity/FieldStorageConfig.php
+++ b/core/modules/field/src/Entity/FieldStorageConfig.php
@@ -755,85 +755,4 @@ public function isDeletable() {
     return !$this->deleted && !$this->persist_with_no_fields && count($this->getBundles()) == 0;
   }
 
-  /**
-   * Creates a new data definition object.
-   *
-   * This method is typically used by
-   * \Drupal\Core\TypedData\TypedDataManager::createDataDefinition() to build a
-   * definition object for an arbitrary data type. When the definition class is
-   * known, it is recommended to directly use the static create() method on that
-   * class instead; e.g.:
-   *
-   * @code
-   *   $map_definition = \Drupal\Core\TypedData\MapDataDefinition::create();
-   * @endcode
-   *
-   * @param string $data_type
-   *   The data type, for which a data definition should be created.
-   *
-   * @throws \InvalidArgumentException
-   *   If an unsupported data type gets passed to the class; e.g., 'string' to a
-   *   definition class handling 'entity:* data types.
-   *
-   * @return static
-   */
-  public static function createFromDataType($data_type) {
-    // TODO: Implement createFromDataType() method.
-  }
-
-  /**
-   * Returns the data type of the data.
-   *
-   * @return string
-   *   The data type.
-   */
-  public function getDataType() {
-    // TODO: Implement getDataType() method.
-  }
-
-  /**
-   * Returns whether the data is multi-valued, i.e. a list of data items.
-   *
-   * This is equivalent to checking whether the data definition implements the
-   * \Drupal\Core\TypedData\ListDefinitionInterface interface.
-   *
-   * @return bool
-   *   Whether the data is multi-valued.
-   */
-  public function isList() {
-    // TODO: Implement isList() method.
-  }
-
-  /**
-   * Determines whether the data is read-only.
-   *
-   * @return bool
-   *   Whether the data is read-only.
-   */
-  public function isReadOnly() {
-    // TODO: Implement isReadOnly() method.
-  }
-
-  /**
-   * Determines whether the data value is computed.
-   *
-   * For example, data could be computed depending on some other values.
-   *
-   * @return bool
-   *   Whether the data value is computed.
-   */
-  public function isComputed() {
-    // TODO: Implement isComputed() method.
-  }
-
-  /**
-   * Returns the class used for creating the typed data object.
-   *
-   * If not specified, the default class of the data type will be returned.
-   *
-   * @return string
-   *   The class used for creating the typed data object.
-   */
-  public function getClass() {
-    // TODO: Implement getClass() method.
-  }}
+}
diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index 763836d..2a20fe5 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -495,7 +495,7 @@
  * );
  * \Drupal::cache()->set($cid, $data, CacheBackendInterface::CACHE_PERMANENT, $tags);
  *
- * // nvalidate all cache items with certain tags.
+ * // Invalidate all cache items with certain tags.
  * \Drupal\Core\Cache\Cache::invalidateTags(array('user:1'));
  * @endcode
  *
diff --git a/core/modules/system/src/Tests/Cache/ChainedFastBackendUnitTest.php b/core/modules/system/src/Tests/Cache/ChainedFastBackendUnitTest.php
index 0cf3883..6b06d04 100644
--- a/core/modules/system/src/Tests/Cache/ChainedFastBackendUnitTest.php
+++ b/core/modules/system/src/Tests/Cache/ChainedFastBackendUnitTest.php
@@ -25,7 +25,7 @@ class ChainedFastBackendUnitTest extends GenericCacheBackendUnitTestBase {
    *   A new ChainedFastBackend object.
    */
   protected function createCacheBackend($bin) {
-    $consistent_backend = new DatabaseBackend($this->container->get('database'), \Drupal::service('cache_tags_storage'), $bin);
+    $consistent_backend = new DatabaseBackend(\Drupal::service('database'), \Drupal::service('cache_tags_storage'), $bin);
     $fast_backend = new PhpBackend($bin, \Drupal::service('cache_tags_storage'));
     return new ChainedFastBackend($consistent_backend, $fast_backend, $bin);
   }
diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index ffc5a27..e4fc1d7 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -198,18 +198,18 @@ public function getStringTranslationStub() {
   /**
    * Sets up a container with a cache tags invalidator.
    *
-   * @param \Drupal\Core\Cache\CacheTagsInvalidatorInterface $cache_tags_handler
+   * @param \Drupal\Core\Cache\CacheTagsInvalidatorInterface $cache_tags_validator
    *   The cache tags invalidator.
    *
    * @return \Symfony\Component\DependencyInjection\ContainerInterface|\PHPUnit_Framework_MockObject_MockObject
    *   The container with the cache tags invalidator service.
    */
-  protected function getContainerWithCacheTagsInvalidator(CacheTagsInvalidatorInterface $cache_tags_handler) {
+  protected function getContainerWithCacheTagsInvalidator(CacheTagsInvalidatorInterface $cache_tags_validator) {
     $container = $this->getMock('Symfony\Component\DependencyInjection\ContainerInterface');
     $container->expects($this->any())
       ->method('get')
       ->with('cache_tags_invalidator')
-      ->will($this->returnValue($cache_tags_handler));
+      ->will($this->returnValue($cache_tags_validator));
 
     \Drupal::setContainer($container);
     return $container;