diff --git a/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php b/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
index 1c6ebd8..541e127 100644
--- a/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
+++ b/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
@@ -25,8 +25,8 @@
   /**
    * Overrides \Drupal\Core\TypedData\TypedData::__construct().
    */
-  public function __construct(array $definition, $data_type, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
-    parent::__construct($definition, $data_type, $type_definition, $name, $parent);
+  public function __construct(array $definition, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
+    parent::__construct($definition, $type_definition, $name, $parent);
     // Initialize computed properties by default, such that they get cloned
     // with the whole item.
     foreach ($this->getPropertyDefinitions() as $name => $definition) {
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php b/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
index 3e8fc59..a14926f 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
@@ -61,8 +61,8 @@ class EntityWrapper extends TypedData implements IteratorAggregate, ComplexDataI
   /**
    * Overrides TypedData::__construct().
    */
-  public function __construct(array $definition, $data_type, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
-    parent::__construct($definition, $data_type, $type_definition, $name, $parent);
+  public function __construct(array $definition, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
+    parent::__construct($definition, $type_definition, $name, $parent);
     $this->entityType = isset($this->definition['constraints']['EntityType']) ? $this->definition['constraints']['EntityType'] : NULL;
   }
 
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/Field.php b/core/lib/Drupal/Core/Entity/Field/Type/Field.php
index b3e3474..3b7cb98 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/Field.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/Field.php
@@ -36,8 +36,8 @@ class Field extends ItemList implements FieldInterface {
   /**
    * Overrides TypedData::__construct().
    */
-  public function __construct(array $definition, $data_type, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
-    parent::__construct($definition, $data_type, $type_definition, $name, $parent);
+  public function __construct(array $definition, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
+    parent::__construct($definition, $type_definition, $name, $parent);
     // Always initialize one empty item as most times a value for at least one
     // item will be present. That way prototypes created by
     // \Drupal\Core\TypedData\TypedDataManager::getPropertyInstance() will
diff --git a/core/lib/Drupal/Core/TypedData/TypedData.php b/core/lib/Drupal/Core/TypedData/TypedData.php
index fd9558a..be375a7 100644
--- a/core/lib/Drupal/Core/TypedData/TypedData.php
+++ b/core/lib/Drupal/Core/TypedData/TypedData.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core\TypedData;
 
-use Drupal\Component\Plugin\PluginBase;
+use Drupal\Component\Plugin\PluginInspectionInterface;
 
 /**
  * The abstract base class for typed data.
@@ -15,7 +15,7 @@
  * Classes deriving from this base class have to declare $value
  * or override getValue() or setValue().
  */
-abstract class TypedData extends PluginBase implements TypedDataInterface {
+abstract class TypedData implements TypedDataInterface, PluginInspectionInterface {
 
   /**
    * The data definition.
@@ -25,6 +25,13 @@
   protected $definition;
 
   /**
+   * The type definition.
+   *
+   * @var array
+   */
+  protected $typeDefinition;
+
+  /**
    * The property name.
    *
    * @var string
@@ -43,8 +50,6 @@
    *
    * @param array $definition
    *   The data definition.
-   * @param string $data_type
-   *   The data type
    * @param array $type_definition
    *   The data type definition.
    * @param string $name
@@ -56,10 +61,9 @@
    *
    * @see Drupal\Core\TypedData\TypedDataManager::create()
    */
-  public function __construct(array $definition, $data_type, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
+  public function __construct(array $definition, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
     $this->definition = $definition;
-    $this->pluginId = $data_type;
-    $this->pluginDefinition = $type_definition;
+    $this->typeDefinition = $type_definition;
     $this->parent = $parent;
     $this->name = $name;
   }
@@ -72,6 +76,20 @@ public function getType() {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function getPluginId() {
+    return $this->definition['type'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getPluginDefinition() {
+    return $this->typeDefinition;
+  }
+  
+  /**
    * Implements \Drupal\Core\TypedData\TypedDataInterface::getDefinition().
    */
   public function getDefinition() {
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataFactory.php b/core/lib/Drupal/Core/TypedData/TypedDataFactory.php
index 1521eff..0dbd3e6 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataFactory.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataFactory.php
@@ -58,7 +58,7 @@ public function createInstance($plugin_id, array $configuration, $name = NULL, $
       throw new PluginException(sprintf('The plugin (%s) did not specify an instance class.', $plugin_id));
     }
 
-    return new $class($configuration, $plugin_id, $type_definition, $name, $parent);
+    return new $class($configuration, $type_definition, $name, $parent);
   }
 
 }
diff --git a/core/modules/locale/lib/Drupal/locale/LocaleTypedConfig.php b/core/modules/locale/lib/Drupal/locale/LocaleTypedConfig.php
index 8333029..b4df7f1 100644
--- a/core/modules/locale/lib/Drupal/locale/LocaleTypedConfig.php
+++ b/core/modules/locale/lib/Drupal/locale/LocaleTypedConfig.php
@@ -52,11 +52,10 @@ class LocaleTypedConfig extends Element {
    */
   // @todo Figure out signature.
   public function __construct(array $definition, $name, $langcode, \Drupal\locale\LocaleConfigManager $localeConfig) {
-    // @todo parent::__construct() needs a $plugin_id and $plugin_definition,
-    // but not sure how to get those.
-    $data_type = '';
+    // @todo parent::__construct() needs a $type_definition,
+    // but not sure how to get one.
     $type_definition = array();
-    parent::__construct($definition, $data_type, $type_definition, $name);
+    parent::__construct($definition, $type_definition, $name);
     $this->langcode = $langcode;
     $this->localeConfig = $localeConfig;
   }
diff --git a/core/modules/text/lib/Drupal/text/TextProcessed.php b/core/modules/text/lib/Drupal/text/TextProcessed.php
index 4a1679e..7d9f539 100644
--- a/core/modules/text/lib/Drupal/text/TextProcessed.php
+++ b/core/modules/text/lib/Drupal/text/TextProcessed.php
@@ -37,8 +37,8 @@ class TextProcessed extends TypedData {
   /**
    * Overrides TypedData::__construct().
    */
-  public function __construct(array $definition, $data_type, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
-    parent::__construct($definition, $data_type, $type_definition, $name, $parent);
+  public function __construct(array $definition, array $type_definition, $name = NULL, TypedDataInterface $parent = NULL) {
+    parent::__construct($definition, $type_definition, $name, $parent);
 
     if (!isset($definition['settings']['text source'])) {
       throw new InvalidArgumentException("The definition's 'source' key has to specify the name of the text property to be processed.");