diff --git a/core/lib/Drupal/Core/Entity/ContentEntityFormController.php b/core/lib/Drupal/Core/Entity/ContentEntityFormController.php
index e3a4d7e..568d5cb 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityFormController.php
@@ -48,46 +48,14 @@ public static function create(ContainerInterface $container) {
    * {@inheritdoc}
    */
   public function form(array $form, array &$form_state) {
+    $form = parent::form($form, $form_state);
     $this->getFormDisplay($form_state)->buildForm($this->entity, $form, $form_state);
-
-    // Add a process callback so we can assign weights and hide extra fields.
-    $form['#process'][] = array($this, 'processForm');
-
     return $form;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function processForm($element, $form_state, $form) {
-    parent::processForm($element, $form_state, $form);
-
-    $form_display = $this->getFormDisplay($form_state);
-
-    // Assign the weights configured in the form display.
-    // @todo: Once https://drupal.org/node/1875974 provides the missing API,
-    //   only do it for 'extra fields', since other components have been taken
-    //   care of in EntityViewDisplay::buildMultiple().
-    foreach ($form_display->getComponents() as $name => $options) {
-      if (isset($element[$name])) {
-        $element[$name]['#weight'] = $options['weight'];
-      }
-    }
-
-    // Hide extra fields.
-    $extra_fields = field_info_extra_fields($this->entity->getEntityTypeId(), $this->entity->bundle(), 'form');
-    foreach ($extra_fields as $extra_field => $info) {
-      if (!$form_display->getComponent($extra_field)) {
-        $element[$extra_field]['#access'] = FALSE;
-      }
-    }
-
-    return $element;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function validate(array $form, array &$form_state) {
     $this->updateFormLangcode($form_state);
     $entity = $this->buildEntity($form, $form_state);
@@ -137,9 +105,7 @@ public function isDefaultFormLangcode(array $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function buildEntity(array $form, array &$form_state) {
-    $entity = clone $this->entity;
-
+  protected function copyFormValuesToEntity(EntityInterface $entity, array $form, array &$form_state) {
     // First, extract values from widgets.
     $extracted = $this->getFormDisplay($form_state)->extractFormValues($entity, $form, $form_state);
 
@@ -148,18 +114,9 @@ public function buildEntity(array $form, array &$form_state) {
     // that are not being edited within this form untouched.
     foreach ($form_state['values'] as $name => $values) {
       if ($entity->hasField($name) && !isset($extracted[$name])) {
-        $entity->$name = $values;
+        $entity->set($name, $values);
       }
     }
-
-    // Invoke all specified builders for copying form values to entity fields.
-    if (isset($form['#entity_builders'])) {
-      foreach ($form['#entity_builders'] as $function) {
-        call_user_func_array($function, array($entity->getEntityTypeId(), $entity, &$form, &$form_state));
-      }
-    }
-
-    return $entity;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/EntityFormController.php b/core/lib/Drupal/Core/Entity/EntityFormController.php
index cbe920d..28ace6b 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormController.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\entity\Entity\EntityFormDisplay;
 
 /**
  * Base class for entity form controllers.
@@ -134,7 +133,7 @@ protected function init(array &$form_state) {
   public function form(array $form, array &$form_state) {
     $entity = $this->entity;
 
-    // Add a process callback so we can assign weights and hide extra fields.
+    // Add a process callback.
     $form['#process'][] = array($this, 'processForm');
 
     if (!isset($form['langcode'])) {
@@ -331,7 +330,7 @@ public function buildEntity(array $form, array &$form_state) {
     // controller of the current request.
     $form_state['controller'] = $this;
 
-    $this->copyFormValuesToEntity($entity, $form_state);
+    $this->copyFormValuesToEntity($entity, $form, $form_state);
 
     // Invoke all specified builders for copying form values to entity
     // properties.
@@ -352,10 +351,12 @@ public function buildEntity(array $form, array &$form_state) {
    *
    * @param \Drupal\Core\Entity\EntityInterface $entity
    *   The entity the current form should operate upon.
+   * @param array $form
+   *   A nested array of form elements comprising the form.
    * @param array $form_state
    *   An associative array containing the current state of the form.
    */
-  protected function copyFormValuesToEntity(EntityInterface $entity, array $form_state) {
+  protected function copyFormValuesToEntity(EntityInterface $entity, array $form, array &$form_state) {
     // @todo: This relies on a method that only exists for config and content
     //   entities, in a different way. Consider moving this logic to a config
     //   entity specific implementation.
diff --git a/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php b/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
index 35fcab4..29fd6e0 100644
--- a/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
+++ b/core/modules/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php
@@ -164,6 +164,32 @@ public function buildForm(ContentEntityInterface $entity, array &$form, array &$
         $form[$name]['#weight'] = $this->getComponent($name)['weight'];
       }
     }
+
+    // Add a process callback so we can assign weights and hide extra fields.
+    $form['#process'][] = array($this, 'processForm');
+  }
+
+  /**
+   * Process callback: assigns weights and hides extra fields.
+   *
+   * @see \Drupal\entity\Entity\EntityFormDisplay::buildForm()
+   */
+  public function processForm($element, $form_state, $form) {
+    // Assign the weights configured in the form display.
+    foreach ($this->getComponents() as $name => $options) {
+      if (isset($element[$name])) {
+        $element[$name]['#weight'] = $options['weight'];
+      }
+    }
+
+    // Hide extra fields.
+    $extra_fields = field_info_extra_fields($this->targetEntityType, $this->bundle, 'form');
+    foreach ($extra_fields as $extra_field => $info) {
+      if (!$this->getComponent($extra_field)) {
+        $element[$extra_field]['#access'] = FALSE;
+      }
+    }
+    return $element;
   }
 
   /**
diff --git a/core/modules/image/lib/Drupal/image/Form/ImageStyleEditForm.php b/core/modules/image/lib/Drupal/image/Form/ImageStyleEditForm.php
index a589feb..41465a2 100644
--- a/core/modules/image/lib/Drupal/image/Form/ImageStyleEditForm.php
+++ b/core/modules/image/lib/Drupal/image/Form/ImageStyleEditForm.php
@@ -252,7 +252,7 @@ protected function updateEffectWeights(array $effects) {
   /**
    * {@inheritdoc}
    */
-  protected function copyFormValuesToEntity(EntityInterface $entity, array $form_state) {
+  protected function copyFormValuesToEntity(EntityInterface $entity, array $form, array &$form_state) {
     foreach ($form_state['values'] as $key => $value) {
       // Do not copy effects here, see self::updateEffectWeights().
       if ($key != 'effects') {