diff --git a/core/modules/field_ui/field_ui.admin.inc b/core/modules/field_ui/field_ui.admin.inc
index e419063..4c6e464 100644
--- a/core/modules/field_ui/field_ui.admin.inc
+++ b/core/modules/field_ui/field_ui.admin.inc
@@ -58,27 +58,6 @@ function field_ui_fields_list() {
 }
 
 /**
- * Displays a message listing the inactive fields of a given bundle.
- */
-function field_ui_inactive_message($entity_type, $bundle) {
-  $inactive_instances = field_ui_inactive_instances($entity_type, $bundle);
-  if (!empty($inactive_instances)) {
-    $field_types = field_info_field_types();
-
-    foreach ($inactive_instances as $field_name => $instance) {
-      $field = field_info_field($instance['field_name']);
-      $list[] = t('%field (@field_name) field requires the %field_type field type provided by %field_type_module module', array(
-      '%field' => $instance['label'],
-      '@field_name' => $instance['field_name'],
-      '%field_type' => isset($field_types[$field['type']]) ? $field_types[$field['type']]['label'] : $field['type'],
-      '%field_type_module' => $field['module'],
-      ));
-    }
-    drupal_set_message(t('Inactive fields are not shown unless their providing modules are enabled. The following fields are not enabled: !list', array('!list' => theme('item_list', array('items' => $list)))), 'error');
-  }
-}
-
-/**
  * Determines the rendering order of an array representing a tree.
  *
  * Callback for array_reduce() within field_ui_table_pre_render().
@@ -96,40 +75,6 @@ function _field_ui_reduce_order($array, $a) {
 }
 
 /**
- * Returns the region to which a row in the 'Manage fields' screen belongs.
- *
- * This function is used as a #region_callback in
- * Drupal\field_ui\DisplayOverview::form(). It is called during
- * field_ui_table_pre_render().
- */
-function field_ui_field_overview_row_region($row) {
-  switch ($row['#row_type']) {
-    case 'field':
-    case 'extra_field':
-      return 'content';
-    case 'add_new_field':
-      // If no input in 'label', assume the row has not been dragged out of the
-      // 'add new' section.
-      return (!empty($row['label']['#value']) ? 'content' : 'hidden');
-  }
-}
-
-/**
- * Returns the region to which a row in the 'Manage display' screen belongs.
- *
- * This function is used as a #region_callback in
- * Drupal\field_ui\FieldOverview::form(), and is called during
- * field_ui_table_pre_render().
- */
-function field_ui_display_overview_row_region($row) {
-  switch ($row['#row_type']) {
-    case 'field':
-    case 'extra_field':
-      return ($row['format']['type']['#value'] == 'hidden' ? 'hidden' : 'content');
-  }
-}
-
-/**
  * Render API callback: Performs pre-render tasks on field_ui_table elements.
  *
  * This function is assigned as a #pre_render callback in
@@ -162,8 +107,7 @@ function field_ui_table_pre_render($elements) {
         unset($list[$name]);
 
         // Determine the region for the row.
-        $function = $row['#region_callback'];
-        $region_name = $function($row);
+        $region_name = call_user_func($row['#region_callback'], $row);
 
         // Add the element in the tree.
         $target = &$trees[$region_name][''];
@@ -431,30 +375,3 @@ function field_ui_existing_field_options($entity_type, $bundle) {
   }
   return $info;
 }
-
-/**
- * Extracts next redirect path from an array of multiple destinations.
- *
- * @see field_ui_next_destination()
- */
-function field_ui_get_destinations($destinations) {
-  $path = array_shift($destinations);
-  $options = drupal_parse_url($path);
-  if ($destinations) {
-    $options['query']['destinations'] = $destinations;
-  }
-  return array($options['path'], $options);
-}
-
-/**
- * Returns the next redirect path in a multipage sequence.
- */
-function field_ui_next_destination($entity_type, $bundle) {
-  $destinations = !empty($_REQUEST['destinations']) ? $_REQUEST['destinations'] : array();
-  if (!empty($destinations)) {
-    unset($_REQUEST['destinations']);
-    return field_ui_get_destinations($destinations);
-  }
-  $admin_path = Drupal::entityManager()->getAdminPath($entity_type, $bundle);
-  return $admin_path . '/fields';
-}
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php b/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
index cf4f6de..8eda507 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/DisplayOverview.php
@@ -107,7 +107,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
         '#row_type' => 'field',
-        '#region_callback' => 'field_ui_display_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         '#js_settings' => array(
           'rowHandler' => 'field',
           'defaultFormatter' => $field_types[$field['type']]['default_formatter'],
@@ -294,7 +294,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
         '#row_type' => 'extra_field',
-        '#region_callback' => 'field_ui_display_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         '#js_settings' => array('rowHandler' => 'field'),
         'human_name' => array(
           '#markup' => check_plain($extra_field['label']),
@@ -576,4 +576,16 @@ public function multistepAjax($form, &$form_state) {
     // Return the whole table.
     return $form['fields'];
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRowRegion($row) {
+    switch ($row['#row_type']) {
+      case 'field':
+      case 'extra_field':
+        return ($row['format']['type']['#value'] == 'hidden' ? 'hidden' : 'content');
+    }
+  }
+
 }
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php b/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
index f02e2eb..20e17f4 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
@@ -91,7 +91,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
         '#row_type' => 'field',
-        '#region_callback' => 'field_ui_field_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         'label' => array(
           '#markup' => check_plain($instance['label']),
         ),
@@ -163,7 +163,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
         '#row_type' => 'extra_field',
-        '#region_callback' => 'field_ui_field_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         'label' => array(
           '#markup' => check_plain($extra_field['label']),
         ),
@@ -213,7 +213,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf', 'add-new')),
         '#row_type' => 'add_new_field',
-        '#region_callback' => 'field_ui_field_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         'label' => array(
           '#type' => 'textfield',
           '#title' => t('New field label'),
@@ -317,7 +317,7 @@ public function buildForm(array $form, array &$form_state, $entity_type = NULL,
       $table[$name] = array(
         '#attributes' => array('class' => array('draggable', 'tabledrag-leaf', 'add-new')),
         '#row_type' => 'add_new_field',
-        '#region_callback' => 'field_ui_field_overview_row_region',
+        '#region_callback' => array($this, 'getRowRegion'),
         'label' => array(
           '#type' => 'textfield',
           '#title' => t('Existing field label'),
@@ -631,10 +631,29 @@ public function submitForm(array &$form, array &$form_state) {
       $destination = drupal_get_destination();
       $destinations[] = $destination['destination'];
       unset($_GET['destination']);
-      $form_state['redirect'] = field_ui_get_destinations($destinations);
+      $path = array_shift($destinations);
+      $options = drupal_parse_url($path);
+      $options['query']['destinations'] = $destinations;
+      $form_state['redirect'] = array($options['path'], $options);
     }
     else {
       drupal_set_message(t('Your settings have been saved.'));
     }
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRowRegion($row) {
+    switch ($row['#row_type']) {
+      case 'field':
+      case 'extra_field':
+        return 'content';
+      case 'add_new_field':
+        // If no input in 'label', assume the row has not been dragged out of the
+        // 'add new' section.
+        return (!empty($row['label']['#value']) ? 'content' : 'hidden');
+    }
+  }
+
 }
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldDeleteForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldDeleteForm.php
index ec13c50..a35be7f 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldDeleteForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldDeleteForm.php
@@ -107,7 +107,7 @@ public function submitForm(array &$form, array &$form_state) {
     }
 
     $admin_path = $this->entityManager->getAdminPath($this->instance->entity_type, $this->instance->bundle);
-    $form_state['redirect'] = field_ui_get_destinations(array($admin_path . '/fields'));
+    $form_state['redirect'] = "$admin_path/fields";
 
     // Fields are purged on cron. However field module prevents disabling modules
     // when field types they provided are used in a field until it is fully
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
index 8e8d890..bc2d5ab 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
@@ -7,19 +7,18 @@
 
 namespace Drupal\field_ui\Form;
 
-use Drupal\Core\Form\FormInterface;
-use Drupal\field\Plugin\Core\Entity\FieldInstance;
+use Drupal\field\FieldInstanceInterface;
 use Drupal\field\Field;
 
 /**
  * Provides a form for the field settings edit page.
  */
-class FieldEditForm implements FormInterface {
+class FieldEditForm extends FieldInstanceFormBase {
 
   /**
    * The field instance being edited.
    *
-   * @var \Drupal\field\Plugin\Core\Entity\FieldInstance
+   * @var \Drupal\field\FieldInstanceInterface
    */
   protected $instance;
 
@@ -33,8 +32,9 @@ public function getFormID() {
   /**
    * {@inheritdoc}
    */
-  public function buildForm(array $form, array &$form_state, FieldInstance $field_instance = NULL) {
-    $this->instance = $form_state['instance'] = $field_instance;
+  public function buildForm(array $form, array &$form_state, FieldInstanceInterface $field_instance = NULL) {
+    parent::buildForm($form, $form_state, $field_instance);
+
     $field = $this->instance->getField();
     $form['#field'] = $field;
 
@@ -128,7 +128,6 @@ public function validateForm(array &$form, array &$form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, array &$form_state) {
-    form_load_include($form_state, 'inc', 'field_ui', 'field_ui.admin');
     $form_values = $form_state['values'];
     $field_values = $form_values['field'];
 
@@ -152,7 +151,7 @@ public function submitForm(array &$form, array &$form_state) {
     try {
       $field->save();
       drupal_set_message(t('Updated field %label field settings.', array('%label' => $this->instance->label())));
-      $form_state['redirect'] = field_ui_next_destination($this->instance->entity_type, $this->instance->bundle);
+      $form_state['redirect'] = $this->getNextDestination();
     }
     catch (Exception $e) {
       drupal_set_message(t('Attempt to update field %label failed: %message.', array('%label' => $this->instance->label(), '%message' => $e->getMessage())), 'error');
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
index 4803701..d8cc38f 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
@@ -7,49 +7,12 @@
 
 namespace Drupal\field_ui\Form;
 
-use Drupal\Core\Form\FormInterface;
-use Drupal\Core\ControllerInterface;
-use Drupal\field\Plugin\Core\Entity\FieldInstance;
-use Drupal\field\Plugin\Type\Widget\WidgetPluginManager;
-use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\field\FieldInstanceInterface;
 
 /**
  * Provides a form for the field instance settings form.
  */
-class FieldInstanceEditForm implements FormInterface, ControllerInterface {
-
-  /**
-   * The field instance being edited.
-   *
-   * @var \Drupal\field\Plugin\Core\Entity\FieldInstance
-   */
-  protected $instance;
-
-  /**
-   * The field widget plugin manager.
-   *
-   * @var \Drupal\field\Plugin\Type\Widget\WidgetPluginManager
-   */
-  protected $widgetManager;
-
-  /**
-   * Constructs a new FieldInstanceEditForm object.
-   *
-   * @param \Drupal\field\Plugin\Type\Widget\WidgetPluginManager $widget_manager
-   *   The field widget plugin manager.
-   */
-  public function __construct(WidgetPluginManager $widget_manager) {
-    $this->widgetManager = $widget_manager;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('plugin.manager.field.widget')
-    );
-  }
+class FieldInstanceEditForm extends FieldInstanceFormBase {
 
   /**
    * {@inheritdoc}
@@ -61,8 +24,8 @@ public function getFormID() {
   /**
    * {@inheritdoc}
    */
-  public function buildForm(array $form, array &$form_state, FieldInstance $field_instance = NULL) {
-    $this->instance = $form_state['instance'] = $field_instance;
+  public function buildForm(array $form, array &$form_state, FieldInstanceInterface $field_instance = NULL) {
+    parent::buildForm($form, $form_state, $field_instance);
 
     $bundle = $this->instance['bundle'];
     $entity_type = $this->instance['entity_type'];
@@ -216,7 +179,6 @@ public function validateForm(array &$form, array &$form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, array &$form_state) {
-    form_load_include($form_state, 'inc', 'field_ui', 'field_ui.admin');
     $field = $form['#field'];
     $entity = $form['#entity'];
 
@@ -243,7 +205,7 @@ public function submitForm(array &$form, array &$form_state) {
       drupal_set_message(t('Field %label is required and uses the "hidden" widget. You might want to configure a default value.', array('%label' => $this->instance['label'])), 'warning');
     }
 
-    $form_state['redirect'] = field_ui_next_destination($this->instance['entity_type'], $this->instance['bundle']);
+    $form_state['redirect'] = $this->getNextDestination();
   }
 
   /**
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceFormBase.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceFormBase.php
new file mode 100644
index 0000000..a967781
--- /dev/null
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceFormBase.php
@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\field_ui\Form\FieldInstanceFormBase.
+ */
+
+namespace Drupal\field_ui\Form;
+
+use Drupal\Core\Form\FormInterface;
+use Drupal\Core\ControllerInterface;
+use Drupal\Core\Entity\EntityManager;
+use Drupal\field\Plugin\Type\Widget\WidgetPluginManager;
+use Drupal\field\FieldInstanceInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+abstract class FieldInstanceFormBase implements FormInterface, ControllerInterface {
+
+  /**
+   * The field instance being edited.
+   *
+   * @var \Drupal\field\FieldInstanceInterface
+   */
+  protected $instance;
+
+  /**
+   * The field widget plugin manager.
+   *
+   * @var \Drupal\field\Plugin\Type\Widget\WidgetPluginManager
+   */
+  protected $widgetManager;
+
+  /**
+   * The entity manager.
+   *
+   * @var \Drupal\Core\Entity\EntityManager
+   */
+  protected $entityManager;
+
+  /**
+   * Constructs a new field instance form.
+   *
+   * @param \Drupal\Core\Entity\EntityManager $entity_manager
+   *   The entity manager.
+   * @param \Drupal\field\Plugin\Type\Widget\WidgetPluginManager $widget_manager
+   *   The field widget plugin manager.
+   */
+  public function __construct(EntityManager $entity_manager, WidgetPluginManager $widget_manager) {
+    $this->entityManager = $entity_manager;
+    $this->widgetManager = $widget_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.entity'),
+      $container->get('plugin.manager.field.widget')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state, FieldInstanceInterface $field_instance = NULL) {
+    $this->instance = $form_state['instance'] = $field_instance;
+    form_load_include($form_state, 'inc', 'field_ui', 'field_ui.admin');
+  }
+
+  /**
+   * Returns the next redirect path in a multipage sequence.
+   *
+   * @return string|array
+   *   Either the next path, or an array of redirect paths.
+   */
+  protected function getNextDestination() {
+    $destinations = !empty($_REQUEST['destinations']) ? $_REQUEST['destinations'] : array();
+    if (!empty($destinations)) {
+      unset($_REQUEST['destinations']);
+      $path = array_shift($destinations);
+      $options = drupal_parse_url($path);
+      if ($destinations) {
+        $options['query']['destinations'] = $destinations;
+      }
+      return array($options['path'], $options);
+    }
+    $admin_path = $this->entityManager->getAdminPath($this->instance->entity_type, $this->instance->bundle);
+    return $admin_path . '/fields';
+  }
+
+}
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldWidgetTypeForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldWidgetTypeForm.php
index b28083a..a318c74 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldWidgetTypeForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldWidgetTypeForm.php
@@ -7,49 +7,12 @@
 
 namespace Drupal\field_ui\Form;
 
-use Drupal\Core\Form\FormInterface;
-use Drupal\Core\ControllerInterface;
-use Drupal\field\Plugin\Core\Entity\FieldInstance;
-use Drupal\field\Plugin\Type\Widget\WidgetPluginManager;
-use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\field\FieldInstanceInterface;
 
 /**
  * Provides a form for the widget selection form.
  */
-class FieldWidgetTypeForm implements FormInterface, ControllerInterface {
-
-  /**
-   * The field instance being edited.
-   *
-   * @var \Drupal\field\Plugin\Core\Entity\FieldInstance
-   */
-  protected $instance;
-
-  /**
-   * The field widget plugin manager.
-   *
-   * @var \Drupal\field\Plugin\Type\Widget\WidgetPluginManager
-   */
-  protected $widgetManager;
-
-  /**
-   * Constructs a new FieldWidgetTypeForm object.
-   *
-   * @param \Drupal\field\Plugin\Type\Widget\WidgetPluginManager $widget_manager
-   *   The field widget plugin manager.
-   */
-  public function __construct(WidgetPluginManager $widget_manager) {
-    $this->widgetManager = $widget_manager;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('plugin.manager.field.widget')
-    );
-  }
+class FieldWidgetTypeForm extends FieldInstanceFormBase {
 
   /**
    * {@inheritdoc}
@@ -61,9 +24,9 @@ public function getFormID() {
   /**
    * {@inheritdoc}
    */
-  public function buildForm(array $form, array &$form_state, FieldInstance $field_instance = NULL) {
-    $this->instance = $form_state['instance'] = $field_instance;
-    form_load_include($form_state, 'inc', 'field_ui', 'field_ui.admin');
+  public function buildForm(array $form, array &$form_state, FieldInstanceInterface $field_instance = NULL) {
+    parent::buildForm($form, $form_state, $field_instance);
+
     drupal_set_title($this->instance['label']);
 
     $bundle = $this->instance['bundle'];
@@ -132,7 +95,7 @@ public function submitForm(array &$form, array &$form_state) {
       drupal_set_message(t('There was a problem changing the widget for field %label.', array('%label' => $instance['label'])), 'error');
     }
 
-    $form_state['redirect'] = field_ui_next_destination($entity_type, $bundle);
+    $form_state['redirect'] = $this->getNextDestination();
   }
 
 }
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/OverviewBase.php b/core/modules/field_ui/lib/Drupal/field_ui/OverviewBase.php
index a8cd891..e576d5d 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/OverviewBase.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/OverviewBase.php
@@ -130,4 +130,13 @@ public function getRegionOptions() {
     return $options;
   }
 
+  /**
+   * Returns the region to which a row in the overview screen belongs.
+   *
+   * This function is to be used as a #region_callback in
+   * \Drupal\field_ui\Form\OverviewBase::form(), and is called during
+   * field_ui_table_pre_render().
+   */
+  abstract public function getRowRegion($row);
+
 }