diff --git a/core/modules/user/src/PrivateTempStore.php b/core/modules/user/src/PrivateTempStore.php
index 81503a4..63bc5bc 100644
--- a/core/modules/user/src/PrivateTempStore.php
+++ b/core/modules/user/src/PrivateTempStore.php
@@ -108,6 +108,13 @@ public function get($key) {
   /**
    * {@inheritdoc}
    */
+  public function getIfOwner($key) {
+    return $this->get($key);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function set($key, $value) {
     $key = $this->createkey($key);
     if (!$this->lockBackend->acquire($key)) {
@@ -132,6 +139,13 @@ public function set($key, $value) {
   /**
    * {@inheritdoc}
    */
+  public function setIfOwner($key, $value) {
+    $this->set($key, $value);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function getMetadata($key) {
     $key = $this->createkey($key);
     // Fetch the key/value pair and its metadata.
@@ -169,6 +183,13 @@ public function delete($key) {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function deleteIfOwner($key) {
+    return $this->delete($key);
+  }
+
+  /**
    * Ensures that the key is unique for a user.
    *
    * @param string $key
diff --git a/core/modules/user/src/SharedTempStore.php b/core/modules/user/src/SharedTempStore.php
index e5d2492..706f5d2 100644
--- a/core/modules/user/src/SharedTempStore.php
+++ b/core/modules/user/src/SharedTempStore.php
@@ -114,18 +114,10 @@ public function get($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 == $this->owner)) {
+    if (($object = $this->storage->get($key)) && ($object->owner == $this->getOwner())) {
       return $object->data;
     }
   }
@@ -143,7 +135,7 @@ public function getIfOwner($key) {
    */
   public function setIfNotExists($key, $value) {
     $value = (object) array(
-      'owner' => $this->owner,
+      'owner' => $this->getOwner(),
       'data' => $value,
       'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
     );
@@ -151,26 +143,14 @@ public function setIfNotExists($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 $this->user.
+   * {@inheritdoc}
    */
   public function setIfOwner($key, $value) {
     if ($this->setIfNotExists($key, $value)) {
       return TRUE;
     }
 
-    if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
+    if (($object = $this->storage->get($key)) && ($object->owner == $this->getOwner())) {
       $this->set($key, $value);
       return TRUE;
     }
@@ -193,7 +173,7 @@ public function set($key, $value) {
     }
 
     $value = (object) array(
-      'owner' => $this->owner,
+      'owner' => $this->getOwner(),
       'data' => $value,
       'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
     );
@@ -232,22 +212,13 @@ public function delete($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 $this->owner.
+   * {@inheritdoc}
    */
   public function deleteIfOwner($key) {
     if (!$object = $this->storage->get($key)) {
       return TRUE;
     }
-    elseif ($object->owner == $this->owner) {
+    elseif ($object->owner == $this->getOwner()) {
       $this->delete($key);
       return TRUE;
     }
@@ -255,4 +226,11 @@ public function deleteIfOwner($key) {
     return FALSE;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function getOwner() {
+    return $this->owner;
+  }
+
 }
diff --git a/core/modules/user/src/TempStoreInterface.php b/core/modules/user/src/TempStoreInterface.php
index 5f03b72..995cb97 100644
--- a/core/modules/user/src/TempStoreInterface.php
+++ b/core/modules/user/src/TempStoreInterface.php
@@ -24,6 +24,19 @@
   public function get($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 $key
@@ -34,6 +47,23 @@ public function get($key);
   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 $key
@@ -53,4 +83,18 @@ public function getMetadata($key);
    */
   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);
+
 }