diff --git a/core/lib/Drupal/Core/Entity/ContentEntityBase.php b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
index ad1e61e..ad94f29 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -139,7 +139,19 @@
    * {@inheritdoc}
    */
   public static function createDataDefinition($data_type) {
-    return EntityDefinition::create($data_type);
+    $parts = explode(':', $data_type);
+    if ($parts[0] != 'entity') {
+      throw new \InvalidArgumentException('Data type must be in the form of "entity:ENTITY_TYPE:BUNDLE."');
+    }
+    $definition = EntityDefinition::create();
+    // Set the passed entity type and bundle.
+    if (isset($parts[1])) {
+      $definition->setEntityType($parts[1]);
+    }
+    if (isset($parts[2])) {
+      $definition->setBundles(array($parts[2]));
+    }
+    return $definition;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/EntityDefinition.php b/core/lib/Drupal/Core/Entity/EntityDefinition.php
index 502e6e8..6b1d367 100644
--- a/core/lib/Drupal/Core/Entity/EntityDefinition.php
+++ b/core/lib/Drupal/Core/Entity/EntityDefinition.php
@@ -17,26 +17,17 @@ class EntityDefinition extends ComplexDataDefinitionBase implements EntityDefini
   /**
    * Creates a new entity definition.
    *
-   * @param string $type
-   *   (optional) The data type to set. May be of the form
-   *    "entity:ENTITY_TYPE:BUNDLE", whereas the entity type and bundle are
-   *    optional. Defaults to "entity".
+   * @param string $entity_type
+   *   (optional) The entity type type, or NULL if unknown. Defaults to NULL.
    *
    * @return static
-   *   A new MapDefinition object.
+   *   A new EntityDefinition object.
    */
-  public static function create($type = 'entity') {
-    $parts = explode(':', $type);
-    if ($parts[0] != 'entity') {
-      throw new \InvalidArgumentException('Data type must be in the form of "entity:ENTITY_TYPE:BUNDLE."');
-    }
+  public static function create($entity_type = NULL) {
     $definition = new static(array());
-    // Set the passed entity type and bundle.
-    if (isset($parts[1])) {
-      $definition->setEntityType($parts[1]);
-    }
-    if (isset($parts[2])) {
-      $definition->setBundles(array($parts[2]));
+    // Set the passed entity type.
+    if (isset($entity_type)) {
+      $definition->setEntityType($entity_type);
     }
     return $definition;
   }
@@ -48,6 +39,7 @@ public function getPropertyDefinitions() {
     if (!isset($this->propertyDefinitions)) {
       if ($entity_type = $this->getEntityType()) {
         // @todo: Add support for handling multiple bundles.
+        // See https://drupal.org/node/2169813.
         $bundles = $this->getBundles();
         $bundle = is_array($bundles) && count($bundles) == 1 ? reset($bundles) : NULL;
         $this->propertyDefinitions = \Drupal::entityManager()->getFieldDefinitions($entity_type, $bundle);
diff --git a/core/lib/Drupal/Core/Entity/Plugin/DataType/Entity.php b/core/lib/Drupal/Core/Entity/Plugin/DataType/Entity.php
index 1d9a00f..6d2cfac 100644
--- a/core/lib/Drupal/Core/Entity/Plugin/DataType/Entity.php
+++ b/core/lib/Drupal/Core/Entity/Plugin/DataType/Entity.php
@@ -6,6 +6,7 @@
  */
 
 namespace Drupal\Core\Entity\Plugin\DataType;
+use Drupal\Core\Entity\ContentEntityBase;
 
 /**
  * Defines the base plugin for deriving data types for entity types.
@@ -22,4 +23,11 @@
  */
 abstract class Entity {
 
+  /**
+   * {@inheritdoc}
+   */
+  public static function createDataDefinition($data_type) {
+    return ContentEntityBase::createDataDefinition($data_type);
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/MapItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/MapItem.php
index 079d329..4cfd1b5 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/MapItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/MapItem.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\Field\FieldItemBase;
-use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\TypedData\DataDefinition;
 
 /**
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
index bcd7be9..e08f8af 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
@@ -20,7 +20,7 @@
    * @param string $data_type
    *   The data type, for which a data definition should be created.
    *
-   * @return \Drupal\Core\TypedData\DataDefinitionInterface
+   * @return static
    *   A data definition for the given data type.
    */
   public static function createDataDefinition($data_type);
diff --git a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
index 7170d24..566f574 100644
--- a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
+++ b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\TypedData\DataDefinition;
-use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\file\Plugin\Field\FieldType\FileItem;
 
 /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTypedDataDefinitionTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTypedDataDefinitionTest.php
new file mode 100644
index 0000000..bc9d533
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityTypedDataDefinitionTest.php
@@ -0,0 +1,117 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\system\Tests\TypedData\EntityTypedDataDefinitionTest.
+ */
+
+namespace Drupal\system\Tests\Entity;
+
+use Drupal\Core\Entity\EntityDefinition;
+use Drupal\Core\Field\FieldDefinition;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\TypedData\ComplexDataDefinitionInterface;
+use Drupal\Core\TypedData\ListDefinitionInterface;
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests deriving metadata of entity and field data types.
+ */
+class EntityTypedDataDefinitionTest extends DrupalUnitTestBase {
+
+  /**
+   * The typed data manager to use.
+   *
+   * @var \Drupal\Core\TypedData\TypedDataManager
+   */
+  protected $typedDataManager;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('filter', 'text', 'node');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Entity typed data definitions',
+      'description' => 'Tests reading and deriving metadata of entity and field data types.',
+      'group' => 'Typed Data API',
+    );
+  }
+
+  public function setUp() {
+    parent::setup();
+    $this->typedDataManager = $this->container->get('typed_data_manager');
+  }
+
+  /**
+   * Tests deriving metadata about fields.
+   */
+  public function testFields() {
+    $field_definition = FieldDefinition::create('integer');
+    // Fields are lists of complex data.
+    $this->assertTrue($field_definition instanceof ListDefinitionInterface);
+    $this->assertFalse($field_definition instanceof ComplexDataDefinitionInterface);
+    $field_item_definition = $field_definition->getItemDefinition();
+    $this->assertFalse($field_item_definition instanceof ListDefinitionInterface);
+    $this->assertTrue($field_item_definition instanceof ComplexDataDefinitionInterface);
+
+    // Derive metadata about field item properties.
+    $this->assertEqual(array_keys($field_item_definition->getPropertyDefinitions()), array('value'));
+    $this->assertEqual($field_item_definition->getPropertyDefinition('value')->getDataType(), 'integer');
+    $this->assertEqual($field_item_definition->getMainPropertyName(), 'value');
+    $this->assertNull($field_item_definition->getPropertyDefinition('invalid'));
+
+    // To ease access of field item property metadata, field definitions make
+    // metadata about field item properties on the field level as well.
+    $this->assertTrue($field_definition instanceof FieldDefinitionInterface);
+    $this->assertEqual(array_keys($field_definition->getPropertyDefinitions()), array('value'));
+    $this->assertEqual($field_definition->getPropertyDefinition('value')->getDataType(), 'integer');
+    $this->assertEqual($field_definition->getMainPropertyName(), 'value');
+    $this->assertNull($field_definition->getPropertyDefinition('invalid'));
+
+    // Test using the definition factory for field item lists and field items.
+    $field_item2 = $this->typedDataManager->createDataDefinition('field_item:integer');
+    $this->assertFalse($field_item2 instanceof ListDefinitionInterface);
+    $this->assertTrue($field_item2 instanceof ComplexDataDefinitionInterface);
+    // Comparison should ignore the internal static cache, so compare the
+    // serialized objects instead.
+    $this->assertEqual(serialize($field_item_definition), serialize($field_item2));
+
+    $field_definition2 = $this->typedDataManager->createDataDefinition('field_item:integer', TRUE);
+    $this->assertTrue($field_definition2 instanceof ListDefinitionInterface);
+    $this->assertFalse($field_definition2 instanceof ComplexDataDefinitionInterface);
+    $this->assertEqual(serialize($field_definition), serialize($field_definition2));
+  }
+
+  /**
+   * Tests deriving metadata about entities.
+   */
+  public function testEntities() {
+    $entity_definition = EntityDefinition::create('node');
+    // Entities are complex data.
+    $this->assertFalse($entity_definition instanceof ListDefinitionInterface);
+    $this->assertTrue($entity_definition instanceof ComplexDataDefinitionInterface);
+
+    $field_definitions = $entity_definition->getPropertyDefinitions();
+    // Comparison should ignore the internal static cache, so compare the
+    // serialized objects instead.
+    $this->assertEqual(serialize($field_definitions), serialize(\Drupal::entityManager()->getFieldDefinitions('node')));
+    $this->assertEqual($entity_definition->getPropertyDefinition('title')->getItemDefinition()->getDataType(), 'field_item:text');
+    $this->assertNull($entity_definition->getMainPropertyName());
+    $this->assertNull($entity_definition->getPropertyDefinition('invalid'));
+
+    $entity_definition2 = $this->typedDataManager->createDataDefinition('entity:node', FALSE);
+    $this->assertFalse($entity_definition2 instanceof ListDefinitionInterface);
+    $this->assertTrue($entity_definition2 instanceof ComplexDataDefinitionInterface);
+    $this->assertEqual(serialize($entity_definition), serialize($entity_definition2));
+
+    // Test that definition factory creates the right definitions for all
+    // entity data types variants.
+    $this->assertEqual($this->typedDataManager->createDataDefinition('entity'), EntityDefinition::create());
+    $this->assertEqual($this->typedDataManager->createDataDefinition('entity:node'), EntityDefinition::create('node'));
+  }
+
+}
diff --git a/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php b/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php
deleted file mode 100644
index 0b84cf4..0000000
--- a/core/modules/system/lib/Drupal/system/Tests/TypedData/MetadataTest.php
+++ /dev/null
@@ -1,170 +0,0 @@
-<?php
-
-/**
- * @file
- * Definition of Drupal\system\Tests\TypedData\MetadataTest.
- */
-
-namespace Drupal\system\Tests\TypedData;
-
-use Drupal\Core\Entity\EntityDefinition;
-use Drupal\Core\Field\FieldDefinition;
-use Drupal\Core\Field\FieldDefinitionInterface;
-use Drupal\Core\TypedData\ComplexDataDefinitionInterface;
-use Drupal\Core\TypedData\DataDefinition;
-use Drupal\Core\TypedData\DataDefinitionInterface;
-use Drupal\Core\TypedData\ListDefinition;
-use Drupal\Core\TypedData\ListDefinitionInterface;
-use Drupal\Core\TypedData\MapDefinition;
-use Drupal\simpletest\DrupalUnitTestBase;
-
-/**
- * Tests deriving metadata of core data types.
- */
-class MetadataTest extends DrupalUnitTestBase {
-
-  /**
-   * The typed data manager to use.
-   *
-   * @var \Drupal\Core\TypedData\TypedDataManager
-   */
-  protected $typedDataManager;
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = array('filter', 'text', 'node');
-
-  public static function getInfo() {
-    return array(
-      'name' => 'Metadata',
-      'description' => 'Tests reading and deriving metadata of core data types.',
-      'group' => 'Typed Data API',
-    );
-  }
-
-  public function setUp() {
-    parent::setup();
-    $this->typedDataManager = $this->container->get('typed_data_manager');
-  }
-
-  /**
-   * Tests deriving metadata about list items.
-   */
-  public function testLists() {
-    $list = ListDefinition::create('string');
-    $this->assertTrue($list instanceof ListDefinitionInterface);
-    $item = $list->getItemDefinition();
-    $this->assertTrue($item instanceof DataDefinitionInterface);
-    $this->assertEqual($item->getDataType(), 'string');
-
-    // Test using the definition factory.
-    $list2 = $this->typedDataManager->createDataDefinition('string', TRUE);
-    $this->assertTrue($list2 instanceof ListDefinitionInterface);
-    $this->assertEqual($list, $list2);
-
-    // Test creating a single list item, which is the same as a list of any
-    // items.
-    $list = $this->typedDataManager->createDataDefinition('list');
-    $this->assertTrue($list instanceof ListDefinitionInterface);
-    $this->assertEqual($list->getDataType(), 'list');
-    $this->assertEqual($list->getItemDefinition()->getDataType(), 'any');
-  }
-
-  /**
-   * Tests deriving metadata about maps.
-   */
-  public function testMaps() {
-    $map = MapDefinition::create()
-      ->setPropertyDefinition('one', DataDefinition::create('string'))
-      ->setPropertyDefinition('two', DataDefinition::create('string'))
-      ->setPropertyDefinition('three', DataDefinition::create('string'));
-
-    $this->assertTrue($map instanceof ComplexDataDefinitionInterface);
-
-    // Test retrieving metadata about contained properties.
-    $this->assertEqual(array_keys($map->getPropertyDefinitions()), array('one', 'two', 'three'));
-    $this->assertEqual($map->getPropertyDefinition('one')->getDataType(), 'string');
-    $this->assertNull($map->getMainPropertyName());
-    $this->assertNull($map->getPropertyDefinition('invalid'));
-
-    // Test using the definition factory.
-    $map2 = $this->typedDataManager->createDataDefinition('map');
-    $this->assertTrue($map2 instanceof ComplexDataDefinitionInterface);
-    $map2->setPropertyDefinition('one', DataDefinition::create('string'))
-      ->setPropertyDefinition('two', DataDefinition::create('string'))
-      ->setPropertyDefinition('three', DataDefinition::create('string'));
-    $this->assertEqual($map, $map2);
-  }
-
-  /**
-   * Tests deriving metadata about fields.
-   */
-  public function testFields() {
-    $field = FieldDefinition::create('integer');
-    // Fields are lists of complex data.
-    $this->assertTrue($field instanceof ListDefinitionInterface);
-    $this->assertFalse($field instanceof ComplexDataDefinitionInterface);
-    $field_item = $field->getItemDefinition();
-    $this->assertFalse($field_item instanceof ListDefinitionInterface);
-    $this->assertTrue($field_item instanceof ComplexDataDefinitionInterface);
-
-    // Derive metadata about field item properties.
-    $this->assertEqual(array_keys($field_item->getPropertyDefinitions()), array('value'));
-    $this->assertEqual($field_item->getPropertyDefinition('value')->getDataType(), 'integer');
-    $this->assertEqual($field_item->getMainPropertyName(), 'value');
-    $this->assertNull($field_item->getPropertyDefinition('invalid'));
-
-    // To ease access of field item property metadata, field definitions make
-    // metadata about field item properties on the field level as well.
-    $this->assertTrue($field instanceof FieldDefinitionInterface);
-    $this->assertEqual(array_keys($field->getPropertyDefinitions()), array('value'));
-    $this->assertEqual($field->getPropertyDefinition('value')->getDataType(), 'integer');
-    $this->assertEqual($field->getMainPropertyName(), 'value');
-    $this->assertNull($field->getPropertyDefinition('invalid'));
-
-    // Test using the definition factory for field item lists and field items.
-    $field_item2 = $this->typedDataManager->createDataDefinition('field_item:integer');
-    $this->assertFalse($field_item2 instanceof ListDefinitionInterface);
-    $this->assertTrue($field_item2 instanceof ComplexDataDefinitionInterface);
-    // Comparison should ignore the internal static cache, so compare the
-    // serialized objects instead.
-    $this->assertEqual(serialize($field_item), serialize($field_item2));
-
-    $field2 = $this->typedDataManager->createDataDefinition('field_item:integer', TRUE);
-    $this->assertTrue($field2 instanceof ListDefinitionInterface);
-    $this->assertFalse($field2 instanceof ComplexDataDefinitionInterface);
-    $this->assertEqual(serialize($field), serialize($field2));
-  }
-
-  /**
-   * Tests deriving metadata about entities.
-   */
-  public function testEntities() {
-    $entity = EntityDefinition::create('entity:node');
-    // Entities are complex data.
-    $this->assertFalse($entity instanceof ListDefinitionInterface);
-    $this->assertTrue($entity instanceof ComplexDataDefinitionInterface);
-
-    $fields = $entity->getPropertyDefinitions();
-    // Comparison should ignore the internal static cache, so compare the
-    // serialized objects instead.
-    $this->assertEqual(serialize($fields), serialize(\Drupal::entityManager()->getFieldDefinitions('node')));
-    $this->assertEqual($entity->getPropertyDefinition('title')->getItemDefinition()->getDataType(), 'field_item:text');
-    $this->assertNull($entity->getMainPropertyName());
-    $this->assertNull($entity->getPropertyDefinition('invalid'));
-
-    $entity2 = $this->typedDataManager->createDataDefinition('entity:node', FALSE);
-    $this->assertFalse($entity2 instanceof ListDefinitionInterface);
-    $this->assertTrue($entity2 instanceof ComplexDataDefinitionInterface);
-    $this->assertEqual(serialize($entity), serialize($entity2));
-
-    // Test that specifying the metadata via the setters is the same.
-    $this->assertEqual(EntityDefinition::create('entity'), EntityDefinition::create());
-    $this->assertEqual(EntityDefinition::create('entity:node'), EntityDefinition::create()->setEntityType('node'));
-    $this->assertEqual(EntityDefinition::create('entity:node:article'), EntityDefinition::create()->setEntityType('node')->setBundles(array('article')));
-  }
-
-}
diff --git a/core/modules/system/lib/Drupal/system/Tests/TypedData/TypedDataDefinitionTest.php b/core/modules/system/lib/Drupal/system/Tests/TypedData/TypedDataDefinitionTest.php
new file mode 100644
index 0000000..962d11e
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/TypedData/TypedDataDefinitionTest.php
@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\system\Tests\TypedData\TypedDataDefinitionTest.
+ */
+
+namespace Drupal\system\Tests\TypedData;
+
+use Drupal\Core\TypedData\ComplexDataDefinitionInterface;
+use Drupal\Core\TypedData\DataDefinition;
+use Drupal\Core\TypedData\DataDefinitionInterface;
+use Drupal\Core\TypedData\ListDefinition;
+use Drupal\Core\TypedData\ListDefinitionInterface;
+use Drupal\Core\TypedData\MapDefinition;
+use Drupal\simpletest\DrupalUnitTestBase;
+
+/**
+ * Tests deriving metadata of core data types.
+ */
+class TypedDataDefinitionTest extends DrupalUnitTestBase {
+
+  /**
+   * The typed data manager to use.
+   *
+   * @var \Drupal\Core\TypedData\TypedDataManager
+   */
+  protected $typedDataManager;
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Typed data definitions',
+      'description' => 'Tests reading and deriving metadata of core data types.',
+      'group' => 'Typed Data API',
+    );
+  }
+
+  public function setUp() {
+    parent::setup();
+    $this->typedDataManager = $this->container->get('typed_data_manager');
+  }
+
+  /**
+   * Tests deriving metadata about list items.
+   */
+  public function testLists() {
+    $list_definition = ListDefinition::create('string');
+    $this->assertTrue($list_definition instanceof ListDefinitionInterface);
+    $item_definition = $list_definition->getItemDefinition();
+    $this->assertTrue($item_definition instanceof DataDefinitionInterface);
+    $this->assertEqual($item_definition->getDataType(), 'string');
+
+    // Test using the definition factory.
+    $list_definition2 = $this->typedDataManager->createDataDefinition('string', TRUE);
+    $this->assertTrue($list_definition2 instanceof ListDefinitionInterface);
+    $this->assertEqual($list_definition, $list_definition2);
+
+    // Test creating a single list item, which is the same as a list of any
+    // items.
+    $list_definition = $this->typedDataManager->createDataDefinition('list');
+    $this->assertTrue($list_definition instanceof ListDefinitionInterface);
+    $this->assertEqual($list_definition->getDataType(), 'list');
+    $this->assertEqual($list_definition->getItemDefinition()->getDataType(), 'any');
+  }
+
+  /**
+   * Tests deriving metadata about maps.
+   */
+  public function testMaps() {
+    $map_definition = MapDefinition::create()
+      ->setPropertyDefinition('one', DataDefinition::create('string'))
+      ->setPropertyDefinition('two', DataDefinition::create('string'))
+      ->setPropertyDefinition('three', DataDefinition::create('string'));
+
+    $this->assertTrue($map_definition instanceof ComplexDataDefinitionInterface);
+
+    // Test retrieving metadata about contained properties.
+    $this->assertEqual(array_keys($map_definition->getPropertyDefinitions()), array('one', 'two', 'three'));
+    $this->assertEqual($map_definition->getPropertyDefinition('one')->getDataType(), 'string');
+    $this->assertNull($map_definition->getMainPropertyName());
+    $this->assertNull($map_definition->getPropertyDefinition('invalid'));
+
+    // Test using the definition factory.
+    $map_definition2 = $this->typedDataManager->createDataDefinition('map');
+    $this->assertTrue($map_definition2 instanceof ComplexDataDefinitionInterface);
+    $map_definition2->setPropertyDefinition('one', DataDefinition::create('string'))
+      ->setPropertyDefinition('two', DataDefinition::create('string'))
+      ->setPropertyDefinition('three', DataDefinition::create('string'));
+    $this->assertEqual($map_definition, $map_definition2);
+  }
+
+}
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
index 0d0565a..d57e303 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\TypedData\DataDefinition;
-use Drupal\Core\Field\FieldDefinitionInterface;
 
 /**
  * Plugin implementation of the 'text_with_summary' field type.