diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
index 040ff47..5d3b60e 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
@@ -554,49 +554,49 @@ protected function defineOptions() {
           'type' => array('default' => 'none'),
           'options' => array('default' => array()),
         ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'cache' => array(
         'contains' => array(
           'type' => array('default' => 'none'),
           'options' => array('default' => array()),
         ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'query' => array(
         'contains' => array(
           'type' => array('default' => 'views_query'),
           'options' => array('default' => array()),
          ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'exposed_form' => array(
         'contains' => array(
           'type' => array('default' => 'basic'),
           'options' => array('default' => array()),
          ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'pager' => array(
         'contains' => array(
           'type' => array('default' => 'mini'),
           'options' => array('default' => array()),
          ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'style' => array(
         'contains' => array(
           'type' => array('default' => 'default'),
           'options' => array('default' => array()),
         ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
       'row' => array(
         'contains' => array(
           'type' => array('default' => 'fields'),
           'options' => array('default' => array()),
         ),
-        'merge_defaults' => 'mergePlugin',
+        'merge_defaults' => array($this, 'mergePlugin'),
       ),
 
       'exposed_block' => array(
@@ -605,34 +605,34 @@ protected function defineOptions() {
 
       'header' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'footer' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'empty' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
 
       // We want these to export last.
       // These are the 5 handler types.
       'relationships' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'fields' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'sorts' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'arguments' => array(
         'default' => array(),
-        'merge_defaults' => 'mergeHandler',
+        'merge_defaults' => array($this, 'mergeHandler'),
       ),
       'filter_groups' => array(
         'contains' => array(
@@ -2753,7 +2753,7 @@ public function mergeDefaults() {
 
     // Find all defined options, that have specified a merge_defaults callback.
     foreach ($defined_options as $type => $definition) {
-      if (!isset($definition['merge_defaults']) || !method_exists($this, $definition['merge_defaults'])) {
+      if (!isset($definition['merge_defaults']) || !is_callable($definition['merge_defaults'])) {
         continue;
       }
       // Switch the type to singular, if it's a plural handler.
@@ -2761,7 +2761,7 @@ public function mergeDefaults() {
         $type = $type_map[$type];
       }
 
-      $this->{$definition['merge_defaults']}($type);
+      call_user_func($definition['merge_defaults'], $type);
     }
   }
 
diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/DisplayUnitTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/DisplayUnitTest.php
index 189ae5a..2d033b9 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/DisplayUnitTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/DisplayUnitTest.php
@@ -62,7 +62,7 @@ public static function getInfo() {
   }
 
   /**
-   * Test the default display options.
+   * Tests the default display options.
    */
   public function testDefaultOptions() {
     // Save the view.
diff --git a/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php b/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
index 079b4a0..db85bb6 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
@@ -151,6 +151,11 @@ protected function testWizardForm() {
     $this->assertTrue(count($result), 'Ensure that the machine name is applied to the name field.');
   }
 
+  /**
+   * Tests default plugin values are populated from the wizard form.
+   *
+   * @see \Drupal\views\Plugin\views\display\DisplayPluginBase::mergeDefaults().
+   */
   public function testWizardDefaultValues() {
     $random_id = strtolower($this->randomName(16));
     // Create a basic view.
@@ -163,7 +168,7 @@ public function testWizardDefaultValues() {
 
     // Make sure the plugin types that should not have empty options don't have.
     // Test against all values is unit tested.
-    // @see Drupal\views\Tests\Plugin\DisplayUnitTest
+    // @see \Drupal\views\Tests\Plugin\DisplayUnitTest
     $view = views_get_view($random_id);
     $displays = $view->storage->get('display');
     foreach (array('query', 'exposed_form', 'pager', 'style', 'row') as $type) {