diff --git a/core/lib/Drupal/Core/Entity/DatabaseStorageController.php b/core/lib/Drupal/Core/Entity/DatabaseStorageController.php
index 744eb23..c016093 100644
--- a/core/lib/Drupal/Core/Entity/DatabaseStorageController.php
+++ b/core/lib/Drupal/Core/Entity/DatabaseStorageController.php
@@ -351,7 +351,7 @@ protected function buildQuery($ids, $revision_id = FALSE) {
   protected function attachLoad(&$queried_entities, $load_revision = FALSE) {
     // Attach field values.
     if ($this->entityInfo['fieldable']) {
-      $this->loadFieldItems($queried_entities, $load_revision ? FIELD_LOAD_REVISION : FIELD_LOAD_CURRENT);
+      $this->loadFieldItems($queried_entities, $load_revision ? static::FIELD_LOAD_REVISION : static::FIELD_LOAD_CURRENT);
     }
 
     // Call hook_entity_load().
@@ -550,7 +550,7 @@ public function getQueryServiceName() {
    * {@inheritdoc}
    */
   protected function doLoadFieldItems($entities, $age) {
-    $load_current = $age == FIELD_LOAD_CURRENT;
+    $load_current = $age == static::FIELD_LOAD_CURRENT;
 
     // Collect entities ids and bundles.
     $bundles = array();
diff --git a/core/lib/Drupal/Core/Entity/EntityStorageControllerInterface.php b/core/lib/Drupal/Core/Entity/EntityStorageControllerInterface.php
index 7d3c5a2..c7f72f7 100644
--- a/core/lib/Drupal/Core/Entity/EntityStorageControllerInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityStorageControllerInterface.php
@@ -21,6 +21,16 @@
 interface EntityStorageControllerInterface {
 
   /**
+   * Load the most recent version of an entity's field data.
+   */
+  const FIELD_LOAD_CURRENT = 'FIELD_LOAD_CURRENT';
+
+  /**
+   * Load the version of an entity's field data specified in the entity.
+   */
+  const FIELD_LOAD_REVISION = 'FIELD_LOAD_REVISION';
+
+  /**
    * Resets the internal, static entity cache.
    *
    * @param $ids
diff --git a/core/lib/Drupal/Core/Entity/FieldableEntityStorageControllerBase.php b/core/lib/Drupal/Core/Entity/FieldableEntityStorageControllerBase.php
index 4911694..5ee2309 100644
--- a/core/lib/Drupal/Core/Entity/FieldableEntityStorageControllerBase.php
+++ b/core/lib/Drupal/Core/Entity/FieldableEntityStorageControllerBase.php
@@ -26,8 +26,10 @@
    * @param array $entities
    *   An array of entities keyed by entity ID.
    * @param int $age
-   *   FIELD_LOAD_CURRENT to load the most recent revision for all fields, or
-   *   FIELD_LOAD_REVISION to load the version indicated by each entity.
+   *   EntityStorageControllerInterface::FIELD_LOAD_CURRENT to load the most
+   *   recent revision for all fields, or
+   *   EntityStorageControllerInterface::FIELD_LOAD_REVISION to load the version
+   *   indicated by each entity.
    */
   protected function loadFieldItems(array $entities, $age) {
     if (empty($entities)) {
@@ -36,7 +38,7 @@ protected function loadFieldItems(array $entities, $age) {
 
     // Only the most current revision of non-deleted fields for cacheable entity
     // types can be cached.
-    $load_current = $age == FIELD_LOAD_CURRENT;
+    $load_current = $age == static::FIELD_LOAD_CURRENT;
     $info = entity_get_info($this->entityType);
     $use_cache = $load_current && $info['field_cache'];
 
@@ -165,8 +167,10 @@ protected function deleteFieldItemsRevision(EntityInterface $entity) {
    * @param array $entities
    *   An array of entities keyed by entity ID.
    * @param int $age
-   *   FIELD_LOAD_CURRENT to load the most recent revision for all fields, or
-   *   FIELD_LOAD_REVISION to load the version indicated by each entity.
+   *   EntityStorageControllerInterface::FIELD_LOAD_CURRENT to load the most
+   *   recent revision for all fields, or
+   *   EntityStorageControllerInterface::FIELD_LOAD_REVISION to load the version
+   *   indicated by each entity.
    */
   abstract protected function doLoadFieldItems($entities, $age);
 
diff --git a/core/lib/Drupal/Core/Entity/Query/QueryBase.php b/core/lib/Drupal/Core/Entity/Query/QueryBase.php
index a6f0723..d3b7b66 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryBase.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Entity\Query;
 
 use Drupal\Core\Database\Query\PagerSelectExtender;
+use Drupal\Core\Entity\EntityStorageControllerInterface;
 
 /**
  * The base entity query class.
@@ -101,11 +102,12 @@
   /**
    * Flag indicating whether to query the current revision or all revisions.
    *
-   * Can be either FIELD_LOAD_CURRENT or FIELD_LOAD_REVISION.
+   * Can be either EntityStorageControllerInterface::FIELD_LOAD_CURRENT or
+   * EntityStorageControllerInterface::FIELD_LOAD_REVISION.
    *
    * @var string
    */
-  protected $age = FIELD_LOAD_CURRENT;
+  protected $age = EntityStorageControllerInterface::FIELD_LOAD_CURRENT;
 
   /**
    * The query pager data.
@@ -232,7 +234,7 @@ public function accessCheck($access_check = TRUE) {
   /**
    * Implements \Drupal\Core\Entity\Query\QueryInterface::age().
    */
-  public function age($age = FIELD_LOAD_CURRENT) {
+  public function age($age = EntityStorageControllerInterface::FIELD_LOAD_CURRENT) {
     $this->age = $age;
     return $this;
   }
diff --git a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
index c82a3da..3a02e8e 100644
--- a/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
+++ b/core/lib/Drupal/Core/Entity/Query/QueryInterface.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Entity\Query;
 
+use Drupal\Core\Entity\EntityStorageControllerInterface;
 use Drupal\Core\Database\Query\AlterableInterface;
 
 /**
@@ -158,13 +159,15 @@ public function accessCheck($access_check = TRUE);
    * @TODO: Once revision tables have been cleaned up, revisit this.
    *
    * @param $age
-   *   - FIELD_LOAD_CURRENT (default): Query the most recent revisions only,
-   *   - FIELD_LOAD_REVISION: Query all revisions.
+   *   - EntityStorageControllerInterface::FIELD_LOAD_CURRENT (default): Query
+   *     the most recent revisions only,
+   *   - EntityStorageControllerInterface::FIELD_LOAD_REVISION: Query all
+   *     revisions.
    *
    * @return \Drupal\Core\Entity\Query\QueryInterface
    *   The called object.
    */
-  public function age($age = FIELD_LOAD_CURRENT);
+  public function age($age = EntityStorageControllerInterface::FIELD_LOAD_CURRENT);
 
   /**
    * Execute the query.
diff --git a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
index e72a586..80ad70a 100644
--- a/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
+++ b/core/lib/Drupal/Core/Entity/Query/Sql/Tables.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Entity\Query\Sql;
 
 use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\Core\Entity\EntityStorageControllerInterface;
 use Drupal\Core\Entity\DatabaseStorageController;
 use Drupal\Core\Entity\Plugin\DataType\EntityReference;
 use Drupal\Core\Entity\Query\QueryException;
@@ -82,7 +83,7 @@ public function addField($field, $type, $langcode) {
     for ($key = 0; $key <= $count; $key ++) {
       // If there is revision support and only the current revision is being
       // queried then use the revision id. Otherwise, the entity id will do.
-      if (!empty($entity_info['entity_keys']['revision']) && $age == FIELD_LOAD_CURRENT) {
+      if (!empty($entity_info['entity_keys']['revision']) && $age == EntityStorageControllerInterface::FIELD_LOAD_CURRENT) {
         // This contains the relevant SQL field to be used when joining entity
         // tables.
         $entity_id_field = $entity_info['entity_keys']['revision'];
@@ -251,7 +252,7 @@ protected function ensureEntityTable($index_prefix, $property, $type, $langcode,
   protected function ensureFieldTable($index_prefix, &$field, $type, $langcode, $base_table, $entity_id_field, $field_id_field) {
     $field_name = $field['field_name'];
     if (!isset($this->fieldTables[$index_prefix . $field_name])) {
-      $table = $this->sqlQuery->getMetaData('age') == FIELD_LOAD_CURRENT ? DatabaseStorageController::_fieldTableName($field) : DatabaseStorageController::_fieldRevisionTableName($field);
+      $table = $this->sqlQuery->getMetaData('age') == EntityStorageControllerInterface::FIELD_LOAD_CURRENT ? DatabaseStorageController::_fieldTableName($field) : DatabaseStorageController::_fieldRevisionTableName($field);
       if ($field['cardinality'] != 1) {
         $this->sqlQuery->addMetaData('simple_query', FALSE);
       }
diff --git a/core/modules/block/tests/lib/Drupal/block/Tests/BlockFormControllerTest.php b/core/modules/block/tests/lib/Drupal/block/Tests/BlockFormControllerTest.php
index c1677c5..d3d2146 100644
--- a/core/modules/block/tests/lib/Drupal/block/Tests/BlockFormControllerTest.php
+++ b/core/modules/block/tests/lib/Drupal/block/Tests/BlockFormControllerTest.php
@@ -15,11 +15,6 @@
   define('BLOCK_REGION_NONE', -1);
 }
 
-// @todo Remove once the constants are replaced with constants on classes.
-if (!defined('FIELD_LOAD_CURRENT')) {
-  define('FIELD_LOAD_CURRENT', 'FIELD_LOAD_CURRENT');
-}
-
 /**
  * Tests the block form controller.
  *
diff --git a/core/modules/field/field.module b/core/modules/field/field.module
index 1a673bc..d3a5db3 100644
--- a/core/modules/field/field.module
+++ b/core/modules/field/field.module
@@ -112,20 +112,6 @@
 const FIELD_BEHAVIOR_CUSTOM = 0x0004;
 
 /**
- * Load the most recent version of an entity's field data.
- *
- * @see field_attach_load().
- */
-const FIELD_LOAD_CURRENT = 'FIELD_LOAD_CURRENT';
-
-/**
- * Load the version of an entity's field data specified in the entity.
- *
- * @see field_attach_load().
- */
-const FIELD_LOAD_REVISION = 'FIELD_LOAD_REVISION';
-
-/**
  * Implements hook_help().
  */
 function field_help($path, $arg) {
diff --git a/core/modules/field/field.views.inc b/core/modules/field/field.views.inc
index 7e24b44..d6d9e97 100644
--- a/core/modules/field/field.views.inc
+++ b/core/modules/field/field.views.inc
@@ -9,6 +9,7 @@
 
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Entity\DatabaseStorageController;
+use Drupal\Core\Entity\EntityStorageControllerInterface;
 use Drupal\field\FieldInterface;
 
 /**
@@ -144,20 +145,20 @@ function field_views_field_default_views_data(FieldInterface $field) {
 
   // Description of the field tables.
   $field_tables = array(
-    FIELD_LOAD_CURRENT => array(
+    EntityStorageControllerInterface::FIELD_LOAD_CURRENT => array(
       'table' => DatabaseStorageController::_fieldTableName($field),
       'alias' => "{$entity_type}__{$field->name}",
     ),
   );
   if ($supports_revisions) {
-    $field_tables[FIELD_LOAD_REVISION] = array(
+    $field_tables[EntityStorageControllerInterface::FIELD_LOAD_REVISION] = array(
       'table' => DatabaseStorageController::_fieldRevisionTableName($field),
       'alias' => "{$entity_type}_revision__{$field->name}",
     );
   }
 
   // Build the relationships between the field table and the entity tables.
-  $table_alias = $field_tables[FIELD_LOAD_CURRENT]['alias'];
+  $table_alias = $field_tables[EntityStorageControllerInterface::FIELD_LOAD_CURRENT]['alias'];
   $data[$table_alias]['table']['join'][$entity_table] = array(
     'left_field' => $entity_info['entity_keys']['id'],
     'field' => 'entity_id',
@@ -166,7 +167,7 @@ function field_views_field_default_views_data(FieldInterface $field) {
     ),
   );
   if ($supports_revisions) {
-    $table_alias = $field_tables[FIELD_LOAD_REVISION]['alias'];
+    $table_alias = $field_tables[EntityStorageControllerInterface::FIELD_LOAD_REVISION]['alias'];
     $data[$table_alias]['table']['join'][$entity_revision_table] = array(
       'left_field' => $entity_info['entity_keys']['revision'],
       'field' => 'revision_id',
@@ -195,7 +196,7 @@ function field_views_field_default_views_data(FieldInterface $field) {
     $table = $table_info['table'];
     $table_alias = $table_info['alias'];
 
-    if ($type == FIELD_LOAD_CURRENT) {
+    if ($type == EntityStorageControllerInterface::FIELD_LOAD_CURRENT) {
       $group = $group_name;
       $field_alias = $field_name;
     }
@@ -216,7 +217,7 @@ function field_views_field_default_views_data(FieldInterface $field) {
     $aliases = array();
     $also_known = array();
     foreach ($all_labels as $label_name => $true) {
-      if ($type == FIELD_LOAD_CURRENT) {
+      if ($type == EntityStorageControllerInterface::FIELD_LOAD_CURRENT) {
         if ($label != $label_name) {
           $aliases[] = array(
             'base' => $entity_table,
@@ -255,7 +256,7 @@ function field_views_field_default_views_data(FieldInterface $field) {
       'entity_tables' => $entity_tables,
       // Default the element type to div, let the UI change it if necessary.
       'element type' => 'div',
-      'is revision' => $type == FIELD_LOAD_REVISION,
+      'is revision' => $type == EntityStorageControllerInterface::FIELD_LOAD_REVISION,
     );
   }
 
@@ -301,7 +302,7 @@ function field_views_field_default_views_data(FieldInterface $field) {
       $table = $table_info['table'];
       $table_alias = $table_info['alias'];
 
-      if ($type == FIELD_LOAD_CURRENT) {
+      if ($type == EntityStorageControllerInterface::FIELD_LOAD_CURRENT) {
         $group = $group_name;
       }
       else {
diff --git a/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php b/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
index 7c7e032..f84ca11 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
@@ -8,6 +8,7 @@
 namespace Drupal\field\Plugin\field\field_type;
 
 use Drupal\Core\Entity\Field\PrepareCacheInterface;
+use Drupal\Core\Entity\EntityStorageControllerInterface;
 use Drupal\field\Plugin\Type\FieldType\ConfigFieldItemBase;
 use Drupal\field\FieldInterface;
 
@@ -100,7 +101,7 @@ public function prepareCache() {
         array($entity_id => $this->getInstance()),
         $langcode,
         &$items,
-        FIELD_LOAD_CURRENT,
+        EntityStorageControllerInterface::FIELD_LOAD_CURRENT,
       );
       call_user_func_array($callback, $args);
       $this->setValue($items[$entity_id][0]);
diff --git a/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php b/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
index 6f09d6f..d86d7e4 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/views/field/Field.php
@@ -202,6 +202,7 @@ public function query($use_groupby = FALSE) {
       $options += is_array($this->options['group_columns']) ? $this->options['group_columns'] : array();
 
       $fields = array();
+      // @todo: What is this?
       $rkey = $this->definition['is revision'] ? 'FIELD_LOAD_REVISION' : 'FIELD_LOAD_CURRENT';
       // Go through the list and determine the actual column name from field api.
       foreach ($options as $column) {
diff --git a/core/modules/node/lib/Drupal/node/NodeStorageController.php b/core/modules/node/lib/Drupal/node/NodeStorageController.php
index 0c4d52d..1360af3 100644
--- a/core/modules/node/lib/Drupal/node/NodeStorageController.php
+++ b/core/modules/node/lib/Drupal/node/NodeStorageController.php
@@ -45,10 +45,10 @@ protected function attachLoad(&$queried_entities, $load_revision = FALSE) {
     }
 
     if ($load_revision) {
-      $this->loadFieldItems($queried_entities, FIELD_LOAD_REVISION);
+      $this->loadFieldItems($queried_entities, static::FIELD_LOAD_REVISION);
     }
     else {
-      $this->loadFieldItems($queried_entities, FIELD_LOAD_CURRENT);
+      $this->loadFieldItems($queried_entities, static::FIELD_LOAD_CURRENT);
     }
 
     // Besides the list of nodes, pass one additional argument to