diff --git a/core/modules/datetime/config/schema/datetime.schema.yml b/core/modules/datetime/config/schema/datetime.schema.yml
index 200751a..a5c50b1 100644
--- a/core/modules/datetime/config/schema/datetime.schema.yml
+++ b/core/modules/datetime/config/schema/datetime.schema.yml
@@ -1,6 +1,6 @@
 # Schema for the configuration files of the Datetime module.
 
-# datetime
+# Datetime file type.
 
 field.storage_settings.datetime:
   type: mapping
@@ -86,7 +86,7 @@ field.widget.settings.datetime_default:
   type: mapping
   label: 'Datetime default display format settings'
 
-# daterange
+# Daterange field type.
 
 field.storage_settings.daterange:
   type: mapping
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeCustomFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeCustomFormatter.php
index 6422759..909f86f 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeCustomFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeCustomFormatter.php
@@ -5,6 +5,7 @@
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\datetime\Plugin\Field\FieldType\DateRangeItem;
 
 /**
  * Plugin implementation of the 'Custom' formatter for 'daterange' fields.
@@ -42,7 +43,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
         /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
         $end_date = $item->end_date;
 
-        if ($this->getFieldSetting('daterange_type') == 'date') {
+        if ($this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATE) {
           // A date without time will pick up the current time, use the default.
           datetime_date_default_time($start_date);
           datetime_date_default_time($end_date);
@@ -105,7 +106,7 @@ public function settingsForm(array $form, FormStateInterface $form_state) {
   public function settingsSummary() {
     $summary = parent::settingsSummary();
 
-    $date = DrupalDateTime::createFromTimestamp(REQUEST_TIME);
+    $date = DrupalDateTime::createFromTimestamp($this->requestStack->getCurrentRequest()->server->get('REQUEST_TIME'));
     $this->setTimeZone($date);
     $summary[] = $this->t('Format: @display', ['@display' => $this->formatDate($date)]);
 
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
index 55c1b94..785fa9a 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeDefaultFormatter.php
@@ -5,6 +5,7 @@
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\datetime\Plugin\Field\FieldType\DateRangeItem;
 
 /**
  * Plugin implementation of the 'Default' formatter for 'daterange' fields.
@@ -42,7 +43,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
         /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
         $end_date = $item->end_date;
 
-        if ($this->getFieldSetting('daterange_type') == 'date') {
+        if ($this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATE) {
           // A date without time will pick up the current time, use the default.
           datetime_date_default_time($start_date);
           datetime_date_default_time($end_date);
@@ -149,7 +150,7 @@ public function settingsForm(array $form, FormStateInterface $form_state) {
   public function settingsSummary() {
     $summary = parent::settingsSummary();
 
-    $date = DrupalDateTime::createFromTimestamp(REQUEST_TIME);
+    $date = DrupalDateTime::createFromTimestamp($this->requestStack->getCurrentRequest()->server->get('REQUEST_TIME'));
     $this->setTimeZone($date);
     $summary[] = $this->t('Format: @display', ['@display' => $this->formatDate($date)]);
 
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeFormatterBase.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeFormatterBase.php
index 9db9053..befe395 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeFormatterBase.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangeFormatterBase.php
@@ -10,6 +10,7 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\RequestStack;
 
 
 /**
@@ -32,6 +33,13 @@
   protected $dateFormatStorage;
 
   /**
+   * The request stack.
+   *
+   * @var \Symfony\Component\HttpFoundation\RequestStack
+   */
+  protected $requestStack;
+
+  /**
    * Constructs a new DateTimeDefaultFormatter.
    *
    * @param string $plugin_id
@@ -52,12 +60,15 @@
    *   The date formatter service.
    * @param \Drupal\Core\Entity\EntityStorageInterface $date_format_storage
    *   The date format entity storage.
+   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
+   *   The request stack used to retrieve the current request.
    */
-  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings, DateFormatterInterface $date_formatter, EntityStorageInterface $date_format_storage) {
+  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, array $third_party_settings, DateFormatterInterface $date_formatter, EntityStorageInterface $date_format_storage, RequestStack $request_stack) {
     parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $view_mode, $third_party_settings);
 
     $this->dateFormatter = $date_formatter;
     $this->dateFormatStorage = $date_format_storage;
+    $this->requestStack = $request_stack;
   }
 
   /**
@@ -73,7 +84,8 @@ public static function create(ContainerInterface $container, array $configuratio
       $configuration['view_mode'],
       $configuration['third_party_settings'],
       $container->get('date.formatter'),
-      $container->get('entity.manager')->getStorage('date_format')
+      $container->get('entity.manager')->getStorage('date_format'),
+      $container->get('request_stack')
     );
   }
 
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangePlainFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangePlainFormatter.php
index 19a5f14..7b77a06 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangePlainFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateRangePlainFormatter.php
@@ -3,6 +3,7 @@
 namespace Drupal\datetime\Plugin\Field\FieldFormatter;
 
 use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\datetime\Plugin\Field\FieldType\DateRangeItem;
 
 /**
  * Plugin implementation of the 'Plain' formatter for 'daterange' fields.
@@ -13,7 +14,7 @@
  *   field_types = {
  *     "daterange"
  *   }
- *)
+ * )
  */
 class DateRangePlainFormatter extends DateRangeFormatterBase {
 
@@ -31,7 +32,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
         /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
         $end_date = $item->end_date;
 
-        if ($this->getFieldSetting('daterange_type') == 'date') {
+        if ($this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATE) {
           // A date without time will pick up the current time, use the default.
           datetime_date_default_time($start_date);
           datetime_date_default_time($end_date);
@@ -67,7 +68,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
    * {@inheritdoc}
    */
   protected function formatDate($date) {
-    $format = $this->getFieldSetting('daterange_type') == 'date' ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
+    $format = $this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATE ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
     $timezone = $this->getSetting('timezone_override');
     return $this->dateFormatter->format($date->getTimestamp(), 'custom', $format, $timezone != '' ? $timezone : NULL);
   }
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php
index 678ddc8..c4abd2d 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php
@@ -15,7 +15,7 @@
  *   field_types = {
  *     "datetime"
  *   }
- *)
+ * )
  */
 class DateTimeCustomFormatter extends DateTimeFormatterBase {
 
diff --git a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php
index 683d75c..a74810a 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php
@@ -14,7 +14,7 @@
  *   field_types = {
  *     "datetime"
  *   }
- *)
+ * )
  */
 class DateTimePlainFormatter extends DateTimeFormatterBase {
 
diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
index a918213..f92955c 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateRangeDatelistWidget.php
@@ -103,7 +103,7 @@ function settingsForm(array $form, FormStateInterface $form_state) {
       '#options' => array('MDY' => t('Month/Day/Year'), 'DMY' => t('Day/Month/Year'), 'YMD' => t('Year/Month/Day')),
     );
 
-    if ($this->getFieldSetting('daterange_type') == 'datetime') {
+    if ($this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATETIME) {
       $element['time_type'] = array(
         '#type' => 'select',
         '#title' => t('Time type'),
@@ -146,7 +146,7 @@ public function settingsSummary() {
     $summary = array();
 
     $summary[] = t('Date part order: @order', array('@order' => $this->getSetting('date_order')));
-    if ($this->getFieldSetting('daterange_type') == 'datetime') {
+    if ($this->getFieldSetting('daterange_type') == DateRangeItem::DATERANGE_TYPE_DATETIME) {
       $summary[] = t('Time type: @time_type', array('@time_type' => $this->getSetting('time_type')));
       $summary[] = t('Time increments: @increment', array('@increment' => $this->getSetting('increment')));
     }