diff --git a/core/lib/Drupal/Core/TempStore/PrivateTempStore.php b/core/lib/Drupal/Core/TempStore/PrivateTempStore.php
index f9d1034705..8e4999f8e8 100644
--- a/core/lib/Drupal/Core/TempStore/PrivateTempStore.php
+++ b/core/lib/Drupal/Core/TempStore/PrivateTempStore.php
@@ -26,7 +26,7 @@
  * you want to be able to share data between users or use it for locking, use
  * \Drupal\Core\TempStore\SharedTempStore.
  */
-class PrivateTempStore {
+class PrivateTempStore implements TempStoreInterface {
 
   /**
    * The key/value storage object used for this data.
@@ -90,13 +90,7 @@ public function __construct(KeyValueStoreExpirableInterface $storage, LockBacken
   }
 
   /**
-   * Retrieves a value from this PrivateTempStore for a given key.
-   *
-   * @param string $key
-   *   The key of the data to retrieve.
-   *
-   * @return mixed
-   *   The data associated with the key, or NULL if the key does not exist.
+   * {@inheritdoc}
    */
   public function get($key) {
     $key = $this->createkey($key);
@@ -106,15 +100,14 @@ public function get($key) {
   }
 
   /**
-   * Stores a particular key/value pair in this PrivateTempStore.
-   *
-   * @param string $key
-   *   The key of the data to store.
-   * @param mixed $value
-   *   The data to store.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
+   */
+  public function getIfOwner($key) {
+    return $this->get($key);
+  }
+
+  /**
+   * {@inheritdoc}
    */
   public function set($key, $value) {
     $key = $this->createkey($key);
@@ -135,14 +128,14 @@ public function set($key, $value) {
   }
 
   /**
-   * Returns the metadata associated with a particular key/value pair.
-   *
-   * @param string $key
-   *   The key of the data to store.
-   *
-   * @return mixed
-   *   An object with the owner and updated time if the key has a value, or
-   *   NULL otherwise.
+   * {@inheritdoc}
+   */
+  public function setIfOwner($key, $value) {
+    $this->set($key, $value);
+  }
+
+  /**
+   * {@inheritdoc}
    */
   public function getMetadata($key) {
     $key = $this->createkey($key);
@@ -156,17 +149,7 @@ public function getMetadata($key) {
   }
 
   /**
-   * Deletes data from the store for a given key and releases the lock on it.
-   *
-   * @param string $key
-   *   The key of the data to delete.
-   *
-   * @return bool
-   *   TRUE if the object was deleted or does not exist, FALSE if it exists but
-   *   is not owned by $this->owner.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
    */
   public function delete($key) {
     $key = $this->createkey($key);
@@ -187,6 +170,13 @@ public function delete($key) {
     return TRUE;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function deleteIfOwner($key) {
+    return $this->delete($key);
+  }
+
   /**
    * Ensures that the key is unique for a user.
    *
diff --git a/core/lib/Drupal/Core/TempStore/SharedTempStore.php b/core/lib/Drupal/Core/TempStore/SharedTempStore.php
index c131a80fd2..0c85e2fcab 100644
--- a/core/lib/Drupal/Core/TempStore/SharedTempStore.php
+++ b/core/lib/Drupal/Core/TempStore/SharedTempStore.php
@@ -35,7 +35,7 @@
  * If you want to be able to ensure that the data belongs to the current user,
  * use \Drupal\Core\TempStore\PrivateTempStore.
  */
-class SharedTempStore {
+class SharedTempStore implements TempStoreInterface {
 
   /**
    * The key/value storage object used for this data.
@@ -99,13 +99,7 @@ public function __construct(KeyValueStoreExpirableInterface $storage, LockBacken
   }
 
   /**
-   * Retrieves a value from this SharedTempStore for a given key.
-   *
-   * @param string $key
-   *   The key of the data to retrieve.
-   *
-   * @return mixed
-   *   The data associated with the key, or NULL if the key does not exist.
+   * {@inheritdoc}
    */
   public function get($key) {
     if ($object = $this->storage->get($key)) {
@@ -114,15 +108,7 @@ public function get($key) {
   }
 
   /**
-   * Retrieves a value from this SharedTempStore for a given key.
-   *
-   * Only returns the value if the value is owned by $this->owner.
-   *
-   * @param string $key
-   *   The key of the data to retrieve.
-   *
-   * @return mixed
-   *   The data associated with the key, or NULL if the key does not exist.
+   * {@inheritdoc}
    */
   public function getIfOwner($key) {
     if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
@@ -151,22 +137,7 @@ public function setIfNotExists($key, $value) {
   }
 
   /**
-   * Stores a particular key/value pair in this SharedTempStore.
-   *
-   * Only stores the given key/value pair if it does not exist yet or is owned
-   * by $this->owner.
-   *
-   * @param string $key
-   *   The key of the data to store.
-   * @param mixed $value
-   *   The data to store.
-   *
-   * @return bool
-   *   TRUE if the data was set, or FALSE if it already exists and is not owned
-   *   by $this->user.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
    */
   public function setIfOwner($key, $value) {
     if ($this->setIfNotExists($key, $value)) {
@@ -182,15 +153,7 @@ public function setIfOwner($key, $value) {
   }
 
   /**
-   * Stores a particular key/value pair in this SharedTempStore.
-   *
-   * @param string $key
-   *   The key of the data to store.
-   * @param mixed $value
-   *   The data to store.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
    */
   public function set($key, $value) {
     if (!$this->lockBackend->acquire($key)) {
@@ -210,14 +173,7 @@ public function set($key, $value) {
   }
 
   /**
-   * Returns the metadata associated with a particular key/value pair.
-   *
-   * @param string $key
-   *   The key of the data to store.
-   *
-   * @return mixed
-   *   An object with the owner and updated time if the key has a value, or
-   *   NULL otherwise.
+   * {@inheritdoc}
    */
   public function getMetadata($key) {
     // Fetch the key/value pair and its metadata.
@@ -230,13 +186,7 @@ public function getMetadata($key) {
   }
 
   /**
-   * Deletes data from the store for a given key and releases the lock on it.
-   *
-   * @param string $key
-   *   The key of the data to delete.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
    */
   public function delete($key) {
     if (!$this->lockBackend->acquire($key)) {
@@ -250,19 +200,7 @@ public function delete($key) {
   }
 
   /**
-   * Deletes data from the store for a given key and releases the lock on it.
-   *
-   * Only delete the given key if it is owned by $this->owner.
-   *
-   * @param string $key
-   *   The key of the data to delete.
-   *
-   * @return bool
-   *   TRUE if the object was deleted or does not exist, FALSE if it exists but
-   *   is not owned by $this->owner.
-   *
-   * @throws \Drupal\Core\TempStore\TempStoreException
-   *   Thrown when a lock for the backend storage could not be acquired.
+   * {@inheritdoc}
    */
   public function deleteIfOwner($key) {
     if (!$object = $this->storage->get($key)) {
diff --git a/core/lib/Drupal/Core/TempStore/TempStoreInterface.php b/core/lib/Drupal/Core/TempStore/TempStoreInterface.php
new file mode 100644
index 0000000000..292123afa0
--- /dev/null
+++ b/core/lib/Drupal/Core/TempStore/TempStoreInterface.php
@@ -0,0 +1,95 @@
+<?php
+
+namespace Drupal\Core\TempStore;
+
+/**
+ * @todo.
+ */
+interface TempStoreInterface {
+
+  /**
+   * Retrieves a value from this TempStore for a given key.
+   *
+   * @param string $key
+   *   The key of the data to retrieve.
+   *
+   * @return mixed
+   *   The data associated with the key, or NULL if the key does not exist.
+   */
+  public function get($key);
+
+  /**
+   * Retrieves a value from this TempStore for a given key.
+   *
+   * Only returns the value if the value is owned by $this->getOwner().
+   *
+   * @param string $key
+   *   The key of the data to retrieve.
+   *
+   * @return mixed
+   *   The data associated with the key, or NULL if the key does not exist.
+   */
+  public function getIfOwner($key);
+
+  /**
+   * Stores a particular key/value pair in this TempStore.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   */
+  public function set($key, $value);
+
+  /**
+   * Stores a particular key/value pair in this TempStore.
+   *
+   * Only stores the given key/value pair if it does not exist yet or is owned
+   * by $this->getOwner().
+   *
+   * @param string $key
+   *   The key of the data to store.
+   * @param mixed $value
+   *   The data to store.
+   *
+   * @return bool
+   *   TRUE if the data was set, or FALSE if it already exists and is not owned
+   *   by $this->user.
+   */
+  public function setIfOwner($key, $value);
+
+  /**
+   * Returns the metadata associated with a particular key/value pair.
+   *
+   * @param string $key
+   *   The key of the data to store.
+   *
+   * @return mixed
+   *   An object with the owner and updated time if the key has a value, or
+   *   NULL otherwise.
+   */
+  public function getMetadata($key);
+
+  /**
+   * Deletes data from the store for a given key and releases the lock on it.
+   *
+   * @param string $key
+   *   The key of the data to delete.
+   */
+  public function delete($key);
+
+  /**
+   * Deletes data from the store for a given key and releases the lock on it.
+   *
+   * Only delete the given key if it is owned by $this->getOwner().
+   *
+   * @param string $key
+   *   The key of the data to delete.
+   *
+   * @return bool
+   *   TRUE if the object was deleted or does not exist, FALSE if it exists but
+   *   is not owned by $this->getOwner().
+   */
+  public function deleteIfOwner($key);
+
+}