.../Core/Entity/ContentEntityNullStorage.php       |  7 +++
 .../DynamicallyFieldableEntityStorageInterface.php |  7 +++
 core/lib/Drupal/Core/Entity/EntityManager.php      | 33 ++++++-----
 .../Drupal/Core/Entity/EntityManagerInterface.php  | 19 ++++++-
 .../Core/Entity/Sql/SqlContentEntityStorage.php    | 11 ++++
 .../Entity/Sql/SqlContentEntityStorageSchema.php   | 25 ++++-----
 .../Entity/Sql/SqlContentEntityStorageTest.php     | 65 ++++++++++++++++++++++
 7 files changed, 138 insertions(+), 29 deletions(-)

diff --git a/core/lib/Drupal/Core/Entity/ContentEntityNullStorage.php b/core/lib/Drupal/Core/Entity/ContentEntityNullStorage.php
index 12aeca3..f31b80e 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityNullStorage.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityNullStorage.php
@@ -138,4 +138,11 @@ public function countFieldData($storage_definition, $as_bool = FALSE) {
     return $as_bool ? FALSE : 0;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function hasData() {
+    return FALSE;
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Entity/DynamicallyFieldableEntityStorageInterface.php b/core/lib/Drupal/Core/Entity/DynamicallyFieldableEntityStorageInterface.php
index 6d12c98..1d20217 100644
--- a/core/lib/Drupal/Core/Entity/DynamicallyFieldableEntityStorageInterface.php
+++ b/core/lib/Drupal/Core/Entity/DynamicallyFieldableEntityStorageInterface.php
@@ -85,6 +85,13 @@ public function purgeFieldData(FieldDefinitionInterface $field_definition, $batc
   public function countFieldData($storage_definition, $as_bool = FALSE);
 
   /**
+   * Determines if the storage contains any data.
+   *
+   * @return bool
+   */
+  public function hasData();
+
+  /**
    * Performs final cleanup after all data of a field has been purged.
    *
    * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $storage_definition
diff --git a/core/lib/Drupal/Core/Entity/EntityManager.php b/core/lib/Drupal/Core/Entity/EntityManager.php
index 128d21d..7d7eded 100644
--- a/core/lib/Drupal/Core/Entity/EntityManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityManager.php
@@ -324,19 +324,7 @@ public function getHandler($entity_type, $handler_type) {
       if (!$class) {
         throw new InvalidPluginDefinitionException($entity_type, sprintf('The "%s" entity type did not specify a %s handler.', $entity_type, $handler_type));
       }
-      if (is_subclass_of($class, 'Drupal\Core\Entity\EntityHandlerInterface')) {
-        $handler = $class::createInstance($this->container, $definition);
-      }
-      else {
-        $handler = new $class($definition);
-      }
-      if (method_exists($handler, 'setModuleHandler')) {
-        $handler->setModuleHandler($this->moduleHandler);
-      }
-      if (method_exists($handler, 'setStringTranslation')) {
-        $handler->setStringTranslation($this->translationManager);
-      }
-      $this->handlers[$handler_type][$entity_type] = $handler;
+      $this->handlers[$handler_type][$entity_type] = $this->createHandlerInstance($class, $definition);
     }
     return $this->handlers[$handler_type][$entity_type];
   }
@@ -344,6 +332,25 @@ public function getHandler($entity_type, $handler_type) {
   /**
    * {@inheritdoc}
    */
+  public function createHandlerInstance($class, EntityTypeInterface $definition = null) {
+    if (is_subclass_of($class, 'Drupal\Core\Entity\EntityHandlerInterface')) {
+      $handler = $class::createInstance($this->container, $definition);
+    }
+    else {
+      $handler = new $class($definition);
+    }
+    if (method_exists($handler, 'setModuleHandler')) {
+      $handler->setModuleHandler($this->moduleHandler);
+    }
+    if (method_exists($handler, 'setStringTranslation')) {
+      $handler->setStringTranslation($this->translationManager);
+    }
+    return $handler;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function getBaseFieldDefinitions($entity_type_id) {
     // Check the static cache.
     if (!isset($this->baseFieldDefinitions[$entity_type_id])) {
diff --git a/core/lib/Drupal/Core/Entity/EntityManagerInterface.php b/core/lib/Drupal/Core/Entity/EntityManagerInterface.php
index 8cf95ee..a1dea1d 100644
--- a/core/lib/Drupal/Core/Entity/EntityManagerInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityManagerInterface.php
@@ -237,7 +237,7 @@ public function getFormObject($entity_type, $operation);
   public function hasHandler($entity_type, $handler_type);
 
   /**
-   * Creates a new handler instance.
+   * Creates a new handler instance for a entity type and handler type.
    *
    * @param string $entity_type
    *   The entity type for this controller.
@@ -252,6 +252,23 @@ public function hasHandler($entity_type, $handler_type);
   public function getHandler($entity_type, $handler_type);
 
   /**
+   * Creates new handler instance.
+   *
+   * Usually \Drupal\Core\Entity\EntityManagerInterface::getHandler() is
+   * preferred since that method has additional checking that the class exists
+   * and has static caches.
+   *
+   * @param mixed $class
+   *   The handler class to instantiate.
+   * @param \Drupal\Core\Entity\EntityTypeInterface $definition
+   *   The entity type definition.
+   *
+   * @return mixed
+   *   A handler instance.
+   */
+  public function createHandlerInstance($class, EntityTypeInterface $definition = null);
+
+  /**
    * Get the bundle info of an entity type.
    *
    * @param string $entity_type
diff --git a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php
index b8db248..2ace5c7 100644
--- a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php
@@ -1765,6 +1765,17 @@ public function countFieldData($storage_definition, $as_bool = FALSE) {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function hasData() {
+    return (bool) $this->database->select($this->getBaseTable(), 'base')
+      ->fields('base')
+      ->countQuery()
+      ->execute()
+      ->fetchField();
+  }
+
+  /**
    * Returns whether the passed field has been already deleted.
    *
    * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $storage_definition
diff --git a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
index dac6584..36459b7 100644
--- a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -178,23 +178,18 @@ public function requiresFieldStorageSchemaChanges(FieldStorageDefinitionInterfac
    * {@inheritdoc}
    */
   public function requiresEntityDataMigration(EntityTypeInterface $entity_type, EntityTypeInterface $original) {
-    // If we're updating from NULL storage, then there's no stored data that
-    // requires migration.
-    // @todo Remove in https://www.drupal.org/node/2335879.
     $original_storage_class = $original->getStorageClass();
-    $null_storage_class = 'Drupal\Core\Entity\ContentEntityNullStorage';
-    if ($original_storage_class == $null_storage_class || is_subclass_of($original_storage_class, $null_storage_class)) {
-      return FALSE;
-    }
 
-    return
-      // If the original storage class is different, then there might be
-      // existing entities in that storage even if the new storage's base
-      // table is empty.
-      // @todo Ask the old storage handler rather than assuming:
-      //   https://www.drupal.org/node/2335879.
-      $entity_type->getStorageClass() != $original_storage_class ||
-      !$this->isTableEmpty($this->storage->getBaseTable());
+    // If the original storage class is different, then there might be existing
+    // entities in that storage even if the new storage's base table is empty.
+    if ($entity_type->getStorageClass() != $original_storage_class) {
+      if (!class_exists($original_storage_class)) {
+        return TRUE;
+      }
+      $original_storage = $this->entityManager->createHandlerInstance($original_storage_class, $original);
+      return $original_storage->hasData();
+    }
+    return $this->storage->hasData();
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageTest.php b/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageTest.php
index 3589a63..5abcaaf 100644
--- a/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/Sql/SqlContentEntityStorageTest.php
@@ -1181,6 +1181,71 @@ public function testLoadMultiplePersistentCacheMiss() {
   }
 
   /**
+   * @covers ::hasData
+   */
+  public function testHasData() {
+    $select_fetch_field = $this->getMockBuilder('\Drupal\Core\Database\StatementInterface')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $select_fetch_field->expects($this->once())
+      ->method('fetchField')
+      ->will($this->returnValue(TRUE));
+
+    $select_execute = $this->getMockBuilder('\Drupal\Core\Database\Query\Select')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $select_execute->expects($this->once())
+      ->method('execute')
+      ->will($this->returnValue($select_fetch_field));
+
+    $select_count_query = $this->getMockBuilder('\Drupal\Core\Database\Query\Select')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $select_count_query->expects($this->once())
+      ->method('countQuery')
+      ->will($this->returnValue($select_execute));
+
+    $database_select = $this->getMockBuilder('\Drupal\Core\Database\Query\Select')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $database_select->expects($this->once())
+      ->method('fields')
+      ->will($this->returnValue($select_count_query));
+
+    $database = $this->getMockBuilder('Drupal\Core\Database\Connection')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $database->expects($this->once())
+      ->method('select')
+      ->will($this->returnValue($database_select));
+
+    $this->container->set('database', $database);
+
+    $this->entityManager->expects($this->any())
+      ->method('getDefinition')
+      ->will($this->returnValue($this->entityType));
+
+    $this->entityManager->expects($this->any())
+      ->method('getFieldStorageDefinitions')
+      ->will($this->returnValue($this->fieldDefinitions));
+
+    $this->entityManager->expects($this->any())
+      ->method('getBaseFieldDefinitions')
+      ->will($this->returnValue($this->fieldDefinitions));
+
+    $this->entityStorage = new SqlContentEntityStorage($this->entityType, $database, $this->entityManager, $this->cache);
+
+    $result = $this->entityStorage->hasData();
+
+    $this->assertTrue($result, 'hasData returned TRUE');
+  }
+
+  /**
    * Tests entity ID sanitization.
    */
   public function testCleanIds() {