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diff --git a/web/core/modules/views/src/ViewExecutable.php b/web/core/modules/views/src/ViewExecutable.php
new file mode 100644
index 000000000..b1861f7b3
--- /dev/null
+++ b/web/core/modules/views/src/ViewExecutable.php
@@ -0,0 +1,2517 @@
+<?php
+
+namespace Drupal\views;
+
+use Drupal\Component\Utility\Html;
+use Drupal\Component\Utility\Tags;
+use Drupal\Core\DependencyInjection\DependencySerializationTrait;
+use Drupal\Core\Routing\RouteProviderInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\views\Plugin\views\display\DisplayRouterInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Exception\RouteNotFoundException;
+
+/**
+ * Represents a view as a whole.
+ *
+ * An object to contain all of the data to generate a view, plus the member
+ * functions to build the view query, execute the query and render the output.
+ */
+class ViewExecutable implements \Serializable {
+  use DependencySerializationTrait;
+
+  /**
+   * The config entity in which the view is stored.
+   *
+   * @var \Drupal\views\Entity\View
+   */
+  public $storage;
+
+  /**
+   * Whether or not the view has been built.
+   *
+   * @todo Group with other static properties.
+   *
+   * @var bool
+   */
+  public $built = FALSE;
+
+  /**
+   * Whether the view has been executed/query has been run.
+   *
+   * @todo Group with other static properties.
+   *
+   * @var bool
+   */
+  public $executed = FALSE;
+
+  /**
+   * Any arguments that have been passed into the view.
+   *
+   * @var array
+   */
+  public $args = [];
+
+  /**
+   * An array of build info.
+   *
+   * @var array
+   */
+  public $build_info = [];
+
+  /**
+   * Whether this view uses AJAX.
+   *
+   * @var bool
+   */
+  protected $ajaxEnabled = FALSE;
+
+  /**
+   * Where the results of a query will go.
+   *
+   * The array must use a numeric index starting at 0.
+   *
+   * @var \Drupal\views\ResultRow[]
+   */
+  public $result = [];
+
+  // May be used to override the current pager info.
+
+  /**
+   * The current page. If the view uses pagination.
+   *
+   * @var int
+   */
+  protected $current_page = NULL;
+
+  /**
+   * The number of items per page.
+   *
+   * @var int
+   */
+  protected $items_per_page = NULL;
+
+  /**
+   * The pager offset.
+   *
+   * @var int
+   */
+  protected $offset = NULL;
+
+  /**
+   * The total number of rows returned from the query.
+   *
+   * @var int
+   */
+  public $total_rows = NULL;
+
+  /**
+   * Attachments to place before the view.
+   *
+   * @var array()
+   */
+  public $attachment_before = [];
+
+  /**
+   * Attachments to place after the view.
+   *
+   * @var array
+   */
+  public $attachment_after = [];
+
+  /**
+   * Feed icons attached to the view.
+   *
+   * @var array
+   */
+  public $feedIcons = [];
+
+  // Exposed widget input
+
+  /**
+   * All the form data from $form_state->getValues().
+   *
+   * @var array
+   */
+  public $exposed_data = [];
+
+  /**
+   * An array of input values from exposed forms.
+   *
+   * @var array
+   */
+  protected $exposed_input = [];
+
+  /**
+   * Exposed widget input directly from the $form_state->getValues().
+   *
+   * @var array
+   */
+  public $exposed_raw_input = [];
+
+  /**
+   * Used to store views that were previously running if we recurse.
+   *
+   * @var \Drupal\views\ViewExecutable[]
+   */
+  public $old_view = [];
+
+  /**
+   * To avoid recursion in views embedded into areas.
+   *
+   * @var \Drupal\views\ViewExecutable[]
+   */
+  public $parent_views = [];
+
+  /**
+   * Whether this view is an attachment to another view.
+   *
+   * @var bool
+   */
+  public $is_attachment = NULL;
+
+  /**
+   * Identifier of the current display.
+   *
+   * @var string
+   */
+  public $current_display;
+
+  /**
+   * Where the $query object will reside.
+   *
+   * @var \Drupal\views\Plugin\views\query\QueryPluginBase
+   */
+  public $query = NULL;
+
+  /**
+   * The used pager plugin used by the current executed view.
+   *
+   * @var \Drupal\views\Plugin\views\pager\PagerPluginBase
+   */
+  public $pager = NULL;
+
+  /**
+   * The current used display plugin.
+   *
+   * @var \Drupal\views\Plugin\views\display\DisplayPluginBase
+   */
+  public $display_handler;
+
+  /**
+   * The list of used displays of the view.
+   *
+   * An array containing Drupal\views\Plugin\views\display\DisplayPluginBase
+   * objects.
+   *
+   * @var \Drupal\views\DisplayPluginCollection
+   */
+  public $displayHandlers;
+
+  /**
+   * The current used style plugin.
+   *
+   * @var \Drupal\views\Plugin\views\style\StylePluginBase
+   */
+  public $style_plugin;
+
+  /**
+   * The current used row plugin, if the style plugin supports row plugins.
+   *
+   * @var \Drupal\views\Plugin\views\row\RowPluginBase
+   */
+  public $rowPlugin;
+
+  /**
+   * Stores the current active row while rendering.
+   *
+   * @var int
+   */
+  public $row_index;
+
+  /**
+   * Allow to override the url of the current view.
+   *
+   * @var \Drupal\Core\Url
+   */
+  public $override_url;
+
+  /**
+   * Allow to override the path used for generated urls.
+   *
+   * @var string
+   */
+  public $override_path = NULL;
+
+  /**
+   * Allow to override the used database which is used for this query.
+   *
+   * @var bool
+   */
+  public $base_database = NULL;
+
+  // Handlers which are active on this view.
+
+  /**
+   * Stores the field handlers which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\field\FieldPluginBase[]
+   */
+  public $field;
+
+  /**
+   * Stores the argument handlers which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\argument\ArgumentPluginBase[]
+   */
+  public $argument;
+
+  /**
+   * Stores the sort handlers which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\sort\SortPluginBase[]
+   */
+  public $sort;
+
+  /**
+   * Stores the filter handlers which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\filter\FilterPluginBase[]
+   */
+  public $filter;
+
+  /**
+   * Stores the relationship handlers which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\relationship\RelationshipPluginBase[]
+   */
+  public $relationship;
+
+  /**
+   * Stores the area handlers for the header which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\area\AreaPluginBase[]
+   */
+  public $header;
+
+  /**
+   * Stores the area handlers for the footer which are initialized on this view.
+   *
+   * @var \Drupal\views\Plugin\views\area\AreaPluginBase[]
+   */
+  public $footer;
+
+  /**
+   * Stores the area handlers for the empty text which are initialized on this view.
+   *
+   * An array containing Drupal\views\Plugin\views\area\AreaPluginBase objects.
+   *
+   * @var \Drupal\views\Plugin\views\area\AreaPluginBase[]
+   */
+  public $empty;
+
+  /**
+   * Stores the current response object.
+   *
+   * @var \Symfony\Component\HttpFoundation\Response
+   */
+  protected $response = NULL;
+
+  /**
+   * Stores the current request object.
+   *
+   * @var \Symfony\Component\HttpFoundation\Request
+   */
+  protected $request;
+
+  /**
+   * Does this view already have loaded it's handlers.
+   *
+   * @todo Group with other static properties.
+   *
+   * @var bool
+   */
+  public $inited;
+
+  /**
+   * The rendered output of the exposed form.
+   *
+   * @var string
+   */
+  public $exposed_widgets;
+
+  /**
+   * If this view has been previewed.
+   *
+   * @var bool
+   */
+  public $preview;
+
+  /**
+   * Force the query to calculate the total number of results.
+   *
+   * @todo Move to the query.
+   *
+   * @var bool
+   */
+  public $get_total_rows;
+
+  /**
+   * Indicates if the sorts have been built.
+   *
+   * @todo Group with other static properties.
+   *
+   * @var bool
+   */
+  public $build_sort;
+
+  /**
+   * Stores the many-to-one tables for performance.
+   *
+   * @var array
+   */
+  public $many_to_one_tables;
+
+  /**
+   * A unique identifier which allows to update multiple views output via js.
+   *
+   * @var string
+   */
+  public $dom_id;
+
+  /**
+   * A render array container to store render related information.
+   *
+   * For example you can alter the array and attach some asset library or JS
+   * settings via the #attached key. This is the required way to add custom
+   * CSS or JS.
+   *
+   * @var array
+   *
+   * @see \Drupal\Core\Render\AttachmentsResponseProcessorInterface::processAttachments()
+   */
+  public $element = [
+    '#attached' => [
+      'library' => ['views/views.module'],
+      'drupalSettings' => [],
+    ],
+    '#cache' => [],
+  ];
+
+  /**
+   * The current user.
+   *
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $user;
+
+  /**
+   * Should the admin links be shown on the rendered view.
+   *
+   * @var bool
+   */
+  protected $showAdminLinks;
+
+  /**
+   * The views data.
+   *
+   * @var \Drupal\views\ViewsData
+   */
+  protected $viewsData;
+
+  /**
+   * The route provider.
+   *
+   * @var \Drupal\Core\Routing\RouteProviderInterface
+   */
+  protected $routeProvider;
+
+  /**
+   * The entity type of the base table, if available.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeInterface|false
+   */
+  protected $baseEntityType;
+
+  /**
+   * Constructs a new ViewExecutable object.
+   *
+   * @param \Drupal\views\ViewEntityInterface $storage
+   *   The view config entity the actual information is stored on.
+   * @param \Drupal\Core\Session\AccountInterface $user
+   *   The current user.
+   * @param \Drupal\views\ViewsData $views_data
+   *   The views data.
+   * @param \Drupal\Core\Routing\RouteProviderInterface $route_provider
+   *   The route provider.
+   */
+  public function __construct(ViewEntityInterface $storage, AccountInterface $user, ViewsData $views_data, RouteProviderInterface $route_provider) {
+    // Reference the storage and the executable to each other.
+    $this->storage = $storage;
+    $this->storage->set('executable', $this);
+    $this->user = $user;
+    $this->viewsData = $views_data;
+    $this->routeProvider = $route_provider;
+  }
+
+  /**
+   * Returns the identifier.
+   *
+   * @return string|null
+   *   The entity identifier, or NULL if the object does not yet have an
+   *   identifier.
+   */
+  public function id() {
+    return $this->storage->id();
+  }
+
+  /**
+   * Saves the view.
+   */
+  public function save() {
+    $this->storage->save();
+  }
+
+  /**
+   * Sets the arguments for the view.
+   *
+   * @param array $args
+   *   The arguments passed to the view.
+   */
+  public function setArguments(array $args) {
+    // The array keys of the arguments will be incorrect if set by
+    // views_embed_view() or \Drupal\views\ViewExecutable:preview().
+    $this->args = array_values($args);
+  }
+
+  /**
+   * Expands the list of used cache contexts for the view.
+   *
+   * @param string $cache_context
+   *   The additional cache context.
+   *
+   * @return $this
+   */
+  public function addCacheContext($cache_context) {
+    $this->element['#cache']['contexts'][] = $cache_context;
+
+    return $this;
+  }
+
+  /**
+   * Sets the current page for the pager.
+   *
+   * @param int $page
+   *   The current page.
+   */
+  public function setCurrentPage($page) {
+    $this->current_page = $page;
+
+    // Calls like ::unserialize() might call this method without a proper $page.
+    // Also check whether the element is pre rendered. At that point, the cache
+    // keys cannot longer be manipulated.
+    if ($page !== NULL && empty($this->element['#pre_rendered'])) {
+      $this->element['#cache']['keys'][] = 'page:' . $page;
+    }
+
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      return $this->pager->setCurrentPage($page);
+    }
+  }
+
+  /**
+   * Gets the current page from the pager.
+   *
+   * @return int
+   *   The current page.
+   */
+  public function getCurrentPage() {
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      return $this->pager->getCurrentPage();
+    }
+
+    if (isset($this->current_page)) {
+      return $this->current_page;
+    }
+  }
+
+  /**
+   * Gets the items per page from the pager.
+   *
+   * @return int
+   *   The items per page.
+   */
+  public function getItemsPerPage() {
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      return $this->pager->getItemsPerPage();
+    }
+
+    if (isset($this->items_per_page)) {
+      return $this->items_per_page;
+    }
+  }
+
+  /**
+   * Sets the items per page on the pager.
+   *
+   * @param int $items_per_page
+   *   The items per page.
+   */
+  public function setItemsPerPage($items_per_page) {
+    // Check whether the element is pre rendered. At that point, the cache keys
+    // cannot longer be manipulated.
+    if (empty($this->element['#pre_rendered'])) {
+      $this->element['#cache']['keys'][] = 'items_per_page:' . $items_per_page;
+    }
+    $this->items_per_page = $items_per_page;
+
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      $this->pager->setItemsPerPage($items_per_page);
+    }
+  }
+
+  /**
+   * Gets the pager offset from the pager.
+   *
+   * @return int
+   *   The pager offset.
+   */
+  public function getOffset() {
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      return $this->pager->getOffset();
+    }
+
+    if (isset($this->offset)) {
+      return $this->offset;
+    }
+  }
+
+  /**
+   * Sets the offset on the pager.
+   *
+   * @param int $offset
+   *   The pager offset.
+   */
+  public function setOffset($offset) {
+    // Check whether the element is pre rendered. At that point, the cache keys
+    // cannot longer be manipulated.
+    if (empty($this->element['#pre_rendered'])) {
+      $this->element['#cache']['keys'][] = 'offset:' . $offset;
+    }
+
+    $this->offset = $offset;
+
+
+    // If the pager is already initialized, pass it through to the pager.
+    if (!empty($this->pager)) {
+      $this->pager->setOffset($offset);
+    }
+  }
+
+  /**
+   * Determines if the view uses a pager.
+   *
+   * @return bool
+   *   TRUE if the view uses a pager, FALSE otherwise.
+   */
+  public function usePager() {
+    if (!empty($this->pager)) {
+      return $this->pager->usePager();
+    }
+  }
+
+  /**
+   * Sets whether or not AJAX should be used.
+   *
+   * If AJAX is used, paging, table sorting, and exposed filters will be fetched
+   * via an AJAX call rather than a page refresh.
+   *
+   * @param bool $ajax_enabled
+   *   TRUE if AJAX should be used, FALSE otherwise.
+   */
+  public function setAjaxEnabled($ajax_enabled) {
+    $this->ajaxEnabled = (bool) $ajax_enabled;
+  }
+
+  /**
+   * Determines whether or not AJAX should be used.
+   *
+   * @return bool
+   *   TRUE if AJAX is enabled, FALSE otherwise.
+   */
+  public function ajaxEnabled() {
+    return $this->ajaxEnabled;
+  }
+
+  /**
+   * Sets the exposed filters input to an array.
+   *
+   * @param string[] $filters
+   *   The values taken from the view's exposed filters and sorts.
+   */
+  public function setExposedInput($filters) {
+    $this->exposed_input = $filters;
+  }
+
+  /**
+   * Figures out what the exposed input for this view is.
+   *
+   * They will be taken from \Drupal::request()->query or from
+   * something previously set on the view.
+   *
+   * @return string[]
+   *   An array containing the exposed input values keyed by the filter and sort
+   *   name.
+   *
+   * @see self::setExposedInput()
+   */
+  public function getExposedInput() {
+    // Fill our input either from \Drupal::request()->query or from something
+    // previously set on the view.
+    if (empty($this->exposed_input)) {
+      // Ensure that we can call the method at any point in time.
+      $this->initDisplay();
+
+      $this->exposed_input = \Drupal::request()->query->all();
+      // unset items that are definitely not our input:
+      foreach (['page', 'q'] as $key) {
+        if (isset($this->exposed_input[$key])) {
+          unset($this->exposed_input[$key]);
+        }
+      }
+
+      // If we have no input at all, check for remembered input via session.
+
+      // If filters are not overridden, store the 'remember' settings on the
+      // default display. If they are, store them on this display. This way,
+      // multiple displays in the same view can share the same filters and
+      // remember settings.
+      $display_id = ($this->display_handler->isDefaulted('filters')) ? 'default' : $this->current_display;
+
+      if (empty($this->exposed_input) && !empty($_SESSION['views'][$this->storage->id()][$display_id])) {
+        $this->exposed_input = $_SESSION['views'][$this->storage->id()][$display_id];
+      }
+    }
+
+    return $this->exposed_input;
+  }
+
+  /**
+   * Sets the display for this view and initializes the display handler.
+   *
+   * @return true
+   *   Always returns TRUE.
+   */
+  public function initDisplay() {
+    if (isset($this->current_display)) {
+      return TRUE;
+    }
+
+    // Initialize the display cache array.
+    $this->displayHandlers = new DisplayPluginCollection($this, Views::pluginManager('display'));
+
+    $this->current_display = 'default';
+    $this->display_handler = $this->displayHandlers->get('default');
+
+    return TRUE;
+  }
+
+  /**
+   * Gets the first display that is accessible to the user.
+   *
+   * @param array|string $displays
+   *   Either a single display id or an array of display ids.
+   *
+   * @return string
+   *   The first accessible display id, at least default.
+   */
+  public function chooseDisplay($displays) {
+    if (!is_array($displays)) {
+      return $displays;
+    }
+
+    $this->initDisplay();
+
+    foreach ($displays as $display_id) {
+      if ($this->displayHandlers->get($display_id)->access($this->user)) {
+        return $display_id;
+      }
+    }
+
+    return 'default';
+  }
+
+  /**
+   * Gets the current display plugin.
+   *
+   * @return \Drupal\views\Plugin\views\display\DisplayPluginBase
+   *   The current display plugin.
+   */
+  public function getDisplay() {
+    if (!isset($this->display_handler)) {
+      $this->initDisplay();
+    }
+
+    return $this->display_handler;
+  }
+
+  /**
+   * Sets the current display.
+   *
+   * @param string $display_id
+   *   The ID of the display to mark as current.
+   *
+   * @return bool
+   *   TRUE if the display was correctly set, FALSE otherwise.
+   */
+  public function setDisplay($display_id = NULL) {
+    // If we have not already initialized the display, do so.
+    if (!isset($this->current_display)) {
+      // This will set the default display and instantiate the default display
+      // plugin.
+      $this->initDisplay();
+    }
+
+    // If no display ID is passed, we either have initialized the default or
+    // already have a display set.
+    if (!isset($display_id)) {
+      return TRUE;
+    }
+
+    $display_id = $this->chooseDisplay($display_id);
+
+    // Ensure the requested display exists.
+    if (!$this->displayHandlers->has($display_id)) {
+      debug(format_string('setDisplay() called with invalid display ID "@display".', ['@display' => $display_id]));
+      return FALSE;
+    }
+
+    // Reset if the display has changed. It could be called multiple times for
+    // the same display, especially in the UI.
+    if ($this->current_display != $display_id) {
+      // Set the current display.
+      $this->current_display = $display_id;
+
+      // Reset the style and row plugins.
+      $this->style_plugin = NULL;
+      $this->plugin_name = NULL;
+      $this->rowPlugin = NULL;
+    }
+
+    if ($display = $this->displayHandlers->get($display_id)) {
+      // Set a shortcut.
+      $this->display_handler = $display;
+      return TRUE;
+    }
+
+    return FALSE;
+  }
+
+  /**
+   * Creates a new display and a display handler instance for it.
+   *
+   * @param string $plugin_id
+   *   (optional) The plugin type from the Views plugin annotation. Defaults to
+   *   'page'.
+   * @param string $title
+   *   (optional) The title of the display. Defaults to NULL.
+   * @param string $id
+   *   (optional) The ID to use, e.g., 'default', 'page_1', 'block_2'. Defaults
+   *   to NULL.
+   *
+   * @return \Drupal\views\Plugin\views\display\DisplayPluginBase
+   *   A new display plugin instance if executable is set, the new display ID
+   *   otherwise.
+   */
+  public function newDisplay($plugin_id = 'page', $title = NULL, $id = NULL) {
+    $this->initDisplay();
+
+    $id = $this->storage->addDisplay($plugin_id, $title, $id);
+    $this->displayHandlers->addInstanceId($id);
+
+    $display = $this->displayHandlers->get($id);
+    $display->newDisplay();
+    return $display;
+  }
+
+  /**
+   * Gets the current style plugin.
+   *
+   * @return \Drupal\views\Plugin\views\style\StylePluginBase
+   *   The current style plugin.
+   */
+  public function getStyle() {
+    if (!isset($this->style_plugin)) {
+      $this->initStyle();
+    }
+
+    return $this->style_plugin;
+  }
+
+  /**
+   * Finds and initializes the style plugin.
+   *
+   * Note that arguments may have changed which style plugin we use, so
+   * check the view object first, then ask the display handler.
+   *
+   * @return bool
+   *   TRUE if the style plugin was or could be initialized, FALSE otherwise.
+   */
+  public function initStyle() {
+    if (isset($this->style_plugin)) {
+      return TRUE;
+    }
+
+    $this->style_plugin = $this->display_handler->getPlugin('style');
+
+    if (empty($this->style_plugin)) {
+      return FALSE;
+    }
+
+    return TRUE;
+  }
+
+  /**
+   * Acquires and attaches all of the handlers.
+   */
+  public function initHandlers() {
+    $this->initDisplay();
+    if (empty($this->inited)) {
+      foreach ($this::getHandlerTypes() as $key => $info) {
+        $this->_initHandler($key, $info);
+      }
+      $this->inited = TRUE;
+    }
+  }
+
+  /**
+   * Gets the current pager plugin.
+   *
+   * @return \Drupal\views\Plugin\views\pager\PagerPluginBase
+   *   The current pager plugin.
+   */
+  public function getPager() {
+    if (!isset($this->pager)) {
+      $this->initPager();
+    }
+
+    return $this->pager;
+  }
+
+  /**
+   * Initializes the pager.
+   *
+   * Like style initialization, pager initialization is held until late to allow
+   * for overrides.
+   */
+  public function initPager() {
+    if (!isset($this->pager)) {
+      $this->pager = $this->display_handler->getPlugin('pager');
+
+      if ($this->pager->usePager()) {
+        $this->pager->setCurrentPage($this->current_page);
+      }
+
+      // These overrides may have been set earlier via $view->set_*
+      // functions.
+      if (isset($this->items_per_page)) {
+        $this->pager->setItemsPerPage($this->items_per_page);
+      }
+
+      if (isset($this->offset)) {
+        $this->pager->setOffset($this->offset);
+      }
+    }
+  }
+
+  /**
+   * Renders the pager, if necessary.
+   *
+   * @param string[] $exposed_input
+   *   The input values from the exposed forms and sorts of the view.
+   *
+   * @return array|string
+   *   The render array of the pager if it's set, blank string otherwise.
+   */
+  public function renderPager($exposed_input) {
+    if (!empty($this->pager) && $this->pager->usePager()) {
+      return $this->pager->render($exposed_input);
+    }
+
+    return '';
+  }
+
+  /**
+   * Creates a list of base tables to be used by the view.
+   *
+   * This is used primarily for the UI. The display must be already initialized.
+   *
+   * @return array
+   *   An array of base tables to be used by the view.
+   */
+  public function getBaseTables() {
+    $base_tables = [
+      $this->storage->get('base_table') => TRUE,
+      '#global' => TRUE,
+    ];
+
+    foreach ($this->display_handler->getHandlers('relationship') as $handler) {
+      $base_tables[$handler->definition['base']] = TRUE;
+    }
+    return $base_tables;
+  }
+
+  /**
+   * Returns the entity type of the base table, if available.
+   *
+   * @return \Drupal\Core\Entity\EntityType|false
+   *   The entity type of the base table, or FALSE if none exists.
+   */
+  public function getBaseEntityType() {
+    if (!isset($this->baseEntityType)) {
+      $view_base_table = $this->storage->get('base_table');
+      $views_data = $this->viewsData->get($view_base_table);
+      if (!empty($views_data['table']['entity type'])) {
+        $entity_type_id = $views_data['table']['entity type'];
+        $this->baseEntityType = \Drupal::entityTypeManager()->getDefinition($entity_type_id);
+      }
+      else {
+        $this->baseEntityType = FALSE;
+      }
+    }
+    return $this->baseEntityType;
+  }
+
+  /**
+   * Runs the preQuery() on all active handlers.
+   */
+  protected function _preQuery() {
+    foreach ($this::getHandlerTypes() as $key => $info) {
+      $handlers = &$this->$key;
+      $position = 0;
+      foreach ($handlers as $id => $handler) {
+        $handlers[$id]->position = $position;
+        $handlers[$id]->preQuery();
+        $position++;
+      }
+    }
+  }
+
+  /**
+   * Runs the postExecute() on all active handlers.
+   */
+  protected function _postExecute() {
+    foreach ($this::getHandlerTypes() as $key => $info) {
+      $handlers = &$this->$key;
+      foreach ($handlers as $id => $handler) {
+        $handlers[$id]->postExecute($this->result);
+      }
+    }
+  }
+
+  /**
+   * Attaches the views handler for the specific type.
+   *
+   * @param string $key
+   *   One of 'argument', 'field', 'sort', 'filter', 'relationship'.
+   * @param array $info
+   *   An array of views handler types use in the view with additional
+   *   information about them.
+   */
+  protected function _initHandler($key, $info) {
+    // Load the requested items from the display onto the object.
+    $this->$key = &$this->display_handler->getHandlers($key);
+
+    // This reference deals with difficult PHP indirection.
+    $handlers = &$this->$key;
+
+    // Run through and test for accessibility.
+    foreach ($handlers as $id => $handler) {
+      if (!$handler->access($this->user)) {
+        unset($handlers[$id]);
+      }
+    }
+  }
+
+  /**
+   * Builds all the arguments.
+   *
+   * @return bool
+   *   TRUE if the arguments were built successfully, FALSE otherwise.
+   */
+  protected function _buildArguments() {
+    // Initially, we want to build sorts and fields. This can change, though,
+    // if we get a summary view.
+    if (empty($this->argument)) {
+      return TRUE;
+    }
+
+    // build arguments.
+    $position = -1;
+    $substitutions = [];
+    $status = TRUE;
+
+    // Get the title.
+    $title = $this->display_handler->getOption('title');
+
+    // Iterate through each argument and process.
+    foreach ($this->argument as $id => $arg) {
+      $position++;
+      $argument = $this->argument[$id];
+
+      if ($argument->broken()) {
+        continue;
+      }
+
+      $argument->setRelationship();
+
+      $arg = isset($this->args[$position]) ? $this->args[$position] : NULL;
+      $argument->position = $position;
+
+      if (isset($arg) || $argument->hasDefaultArgument()) {
+        if (!isset($arg)) {
+          $arg = $argument->getDefaultArgument();
+          // make sure default args get put back.
+          if (isset($arg)) {
+            $this->args[$position] = $arg;
+          }
+          // remember that this argument was computed, not passed on the URL.
+          $argument->is_default = TRUE;
+        }
+
+        // Set the argument, which will also validate that the argument can be set.
+        if (!$argument->setArgument($arg)) {
+          $status = $argument->validateFail($arg);
+          break;
+        }
+
+        if ($argument->isException()) {
+          $arg_title = $argument->exceptionTitle();
+        }
+        else {
+          $arg_title = $argument->getTitle();
+          $argument->query($this->display_handler->useGroupBy());
+        }
+
+        // Add this argument's substitution
+        $substitutions["{{ arguments.$id }}"] = $arg_title;
+        $substitutions["{{ raw_arguments.$id }}"] = strip_tags(Html::decodeEntities($arg));
+
+        // Test to see if we should use this argument's title
+        if (!empty($argument->options['title_enable']) && !empty($argument->options['title'])) {
+          $title = $argument->options['title'];
+        }
+      }
+      else {
+        // determine default condition and handle.
+        $status = $argument->defaultAction();
+        break;
+      }
+
+      // Be safe with references and loops:
+      unset($argument);
+    }
+
+    // set the title in the build info.
+    if (!empty($title)) {
+      $this->build_info['title'] = $title;
+    }
+
+    // Store the arguments for later use.
+    $this->build_info['substitutions'] = $substitutions;
+
+    return $status;
+  }
+
+  /**
+   * Gets the current query plugin.
+   *
+   * @return \Drupal\views\Plugin\views\query\QueryPluginBase
+   *   The current query plugin.
+   */
+  public function getQuery() {
+    if (!isset($this->query)) {
+      $this->initQuery();
+    }
+
+    return $this->query;
+  }
+
+  /**
+   * Initializes the query object for the view.
+   *
+   * @return true
+   *   Always returns TRUE.
+   */
+  public function initQuery() {
+    if (!empty($this->query)) {
+      $class = get_class($this->query);
+      if ($class && $class != 'stdClass') {
+        // return if query is already initialized.
+        return TRUE;
+      }
+    }
+
+    // Create and initialize the query object.
+    $views_data = Views::viewsData()->get($this->storage->get('base_table'));
+    $this->storage->set('base_field', !empty($views_data['table']['base']['field']) ? $views_data['table']['base']['field'] : '');
+    if (!empty($views_data['table']['base']['database'])) {
+      $this->base_database = $views_data['table']['base']['database'];
+    }
+
+    $this->query = $this->display_handler->getPlugin('query');
+    return TRUE;
+  }
+
+  /**
+   * Builds the query for the view.
+   *
+   * @param string $display_id
+   *   The display ID of the view.
+   *
+   * @return bool|null
+   *   TRUE if the view build process was successful, FALSE if setting the
+   *   display fails or NULL if the view has been built already.
+   */
+  public function build($display_id = NULL) {
+    if (!empty($this->built)) {
+      return;
+    }
+
+    if (empty($this->current_display) || $display_id) {
+      if (!$this->setDisplay($display_id)) {
+        return FALSE;
+      }
+    }
+
+    // Let modules modify the view just prior to building it.
+    $module_handler = \Drupal::moduleHandler();
+    $module_handler->invokeAll('views_pre_build', [$this]);
+
+    // Attempt to load from cache.
+    // @todo Load a build_info from cache.
+
+    $start = microtime(TRUE);
+    // If that fails, let's build!
+    $this->build_info = [
+      'query' => '',
+      'count_query' => '',
+      'query_args' => [],
+    ];
+
+    $this->initQuery();
+
+    // Call a module hook and see if it wants to present us with a
+    // pre-built query or instruct us not to build the query for
+    // some reason.
+    // @todo: Implement this. Use the same mechanism Panels uses.
+
+    // Run through our handlers and ensure they have necessary information.
+    $this->initHandlers();
+
+    // Let the handlers interact with each other if they really want.
+    $this->_preQuery();
+
+    if ($this->display_handler->usesExposed()) {
+      /** @var \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginInterface $exposed_form */
+      $exposed_form = $this->display_handler->getPlugin('exposed_form');
+      $this->exposed_widgets = $exposed_form->renderExposedForm();
+      if (!empty($this->build_info['abort'])) {
+        $this->built = TRUE;
+        // Don't execute the query, $form_state, but rendering will still be executed to display the empty text.
+        $this->executed = TRUE;
+        return empty($this->build_info['fail']);
+      }
+    }
+
+    // Build all the relationships first thing.
+    $this->_build('relationship');
+
+    // Set the filtering groups.
+    if (!empty($this->filter)) {
+      $filter_groups = $this->display_handler->getOption('filter_groups');
+      if ($filter_groups) {
+        $this->query->setGroupOperator($filter_groups['operator']);
+        foreach ($filter_groups['groups'] as $id => $operator) {
+          $this->query->setWhereGroup($operator, $id);
+        }
+      }
+    }
+
+    // Build all the filters.
+    $this->_build('filter');
+
+    $this->build_sort = TRUE;
+
+    // Arguments can, in fact, cause this whole thing to abort.
+    if (!$this->_buildArguments()) {
+      $this->build_time = microtime(TRUE) - $start;
+      $this->attachDisplays();
+      return $this->built;
+    }
+
+    // Initialize the style; arguments may have changed which style we use,
+    // so waiting as long as possible is important. But we need to know
+    // about the style when we go to build fields.
+    if (!$this->initStyle()) {
+      $this->build_info['fail'] = TRUE;
+      return FALSE;
+    }
+
+    if ($this->style_plugin->usesFields()) {
+      $this->_build('field');
+    }
+
+    // Build our sort criteria if we were instructed to do so.
+    if (!empty($this->build_sort)) {
+      // Allow the style handler to deal with sorting.
+      if ($this->style_plugin->buildSort()) {
+        $this->_build('sort');
+      }
+      // allow the plugin to build second sorts as well.
+      $this->style_plugin->buildSortPost();
+    }
+
+    // Allow area handlers to affect the query.
+    $this->_build('header');
+    $this->_build('footer');
+    $this->_build('empty');
+
+    // Allow display handler to affect the query:
+    $this->display_handler->query($this->display_handler->useGroupBy());
+
+    // Allow style handler to affect the query:
+    $this->style_plugin->query($this->display_handler->useGroupBy());
+
+    // Allow exposed form to affect the query:
+    if (isset($exposed_form)) {
+      $exposed_form->query();
+    }
+
+    if (\Drupal::config('views.settings')->get('sql_signature')) {
+      $this->query->addSignature($this);
+    }
+
+    // Let modules modify the query just prior to finalizing it.
+    $this->query->alter($this);
+
+    // Only build the query if we weren't interrupted.
+    if (empty($this->built)) {
+      // Build the necessary info to execute the query.
+      $this->query->build($this);
+    }
+
+    $this->built = TRUE;
+    $this->build_time = microtime(TRUE) - $start;
+
+    // Attach displays
+    $this->attachDisplays();
+
+    // Let modules modify the view just after building it.
+    $module_handler->invokeAll('views_post_build', [$this]);
+
+    return TRUE;
+  }
+
+  /**
+   * Builds an individual set of handlers.
+   *
+   * This is an internal method.
+   *
+   * @todo Some filter needs this function, even it is internal.
+   *
+   * @param string $key
+   *    The type of handlers (filter etc.) which should be iterated over to
+   *    build the relationship and query information.
+   */
+  public function _build($key) {
+    $handlers = &$this->$key;
+    foreach ($handlers as $id => $data) {
+
+      if (!empty($handlers[$id]) && is_object($handlers[$id])) {
+        $multiple_exposed_input = [0 => NULL];
+        if ($handlers[$id]->multipleExposedInput()) {
+          $multiple_exposed_input = $handlers[$id]->groupMultipleExposedInput($this->exposed_data);
+        }
+        foreach ($multiple_exposed_input as $group_id) {
+          // Give this handler access to the exposed filter input.
+          if (!empty($this->exposed_data)) {
+            if ($handlers[$id]->isAGroup()) {
+              $converted = $handlers[$id]->convertExposedInput($this->exposed_data, $group_id);
+              $handlers[$id]->storeGroupInput($this->exposed_data, $converted);
+              if (!$converted) {
+                continue;
+              }
+            }
+            $rc = $handlers[$id]->acceptExposedInput($this->exposed_data);
+            $handlers[$id]->storeExposedInput($this->exposed_data, $rc);
+            if (!$rc) {
+              continue;
+            }
+          }
+          $handlers[$id]->setRelationship();
+          $handlers[$id]->query($this->display_handler->useGroupBy());
+        }
+      }
+    }
+  }
+
+  /**
+   * Executes the view's query.
+   *
+   * @param string $display_id
+   *   The machine name of the display, which should be executed.
+   *
+   * @return bool
+   *   TRUE if the view execution was successful, FALSE otherwise. For example,
+   *   an argument could stop the process.
+   */
+  public function execute($display_id = NULL) {
+    if (empty($this->built)) {
+      if (!$this->build($display_id)) {
+        return FALSE;
+      }
+    }
+
+    if (!empty($this->executed)) {
+      return TRUE;
+    }
+
+    // Don't allow to use deactivated displays, but display them on the live preview.
+    if (!$this->display_handler->isEnabled() && empty($this->live_preview)) {
+      $this->build_info['fail'] = TRUE;
+      return FALSE;
+    }
+
+    // Let modules modify the view just prior to executing it.
+    $module_handler = \Drupal::moduleHandler();
+    $module_handler->invokeAll('views_pre_execute', [$this]);
+
+    // Check for already-cached results.
+    /** @var \Drupal\views\Plugin\views\cache\CachePluginBase $cache */
+    if (!empty($this->live_preview)) {
+      $cache = Views::pluginManager('cache')->createInstance('none');
+    }
+    else {
+      $cache = $this->display_handler->getPlugin('cache');
+    }
+
+    if ($cache->cacheGet('results')) {
+      if ($this->pager->usePager()) {
+        $this->pager->total_items = $this->total_rows;
+        $this->pager->updatePageInfo();
+      }
+    }
+    else {
+      $this->query->execute($this);
+      // Enforce the array key rule as documented in
+      // views_plugin_query::execute().
+      $this->result = array_values($this->result);
+      $this->_postExecute();
+      $cache->cacheSet('results');
+    }
+
+    // Let modules modify the view just after executing it.
+    $module_handler->invokeAll('views_post_execute', [$this]);
+
+    return $this->executed = TRUE;
+  }
+
+  /**
+   * Renders this view for a certain display.
+   *
+   * Note: You should better use just the preview function if you want to
+   * render a view.
+   *
+   * @param string $display_id
+   *   The machine name of the display, which should be rendered.
+   *
+   * @return array|null
+   *   A renderable array containing the view output or NULL if the build
+   *   process failed.
+   */
+  public function render($display_id = NULL) {
+    $this->execute($display_id);
+
+    // Check to see if the build failed.
+    if (!empty($this->build_info['fail'])) {
+      return;
+    }
+    if (!empty($this->build_info['denied'])) {
+      return;
+    }
+
+    /** @var \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginInterface $exposed_form */
+    $exposed_form = $this->display_handler->getPlugin('exposed_form');
+    $exposed_form->preRender($this->result);
+
+    $module_handler = \Drupal::moduleHandler();
+
+    // @TODO In the longrun, it would be great to execute a view without
+    //   the theme system at all. See https://www.drupal.org/node/2322623.
+    $active_theme = \Drupal::theme()->getActiveTheme();
+    $themes = array_keys($active_theme->getBaseThemes());
+    $themes[] = $active_theme->getName();
+
+    // Check for already-cached output.
+    /** @var \Drupal\views\Plugin\views\cache\CachePluginBase $cache */
+    if (!empty($this->live_preview)) {
+      $cache = Views::pluginManager('cache')->createInstance('none');
+    }
+    else {
+      $cache = $this->display_handler->getPlugin('cache');
+    }
+
+    // Run preRender for the pager as it might change the result.
+    if (!empty($this->pager)) {
+      $this->pager->preRender($this->result);
+    }
+
+    // Initialize the style plugin.
+    $this->initStyle();
+
+    if (!isset($this->response)) {
+      // Set the response so other parts can alter it.
+      $this->response = new Response('', 200);
+    }
+
+    // Give field handlers the opportunity to perform additional queries
+    // using the entire resultset prior to rendering.
+    if ($this->style_plugin->usesFields()) {
+      foreach ($this->field as $id => $handler) {
+        if (!empty($this->field[$id])) {
+          $this->field[$id]->preRender($this->result);
+        }
+      }
+    }
+
+    $this->style_plugin->preRender($this->result);
+
+    // Let each area handler have access to the result set.
+    $areas = ['header', 'footer'];
+    // Only call preRender() on the empty handlers if the result is empty.
+    if (empty($this->result)) {
+      $areas[] = 'empty';
+    }
+    foreach ($areas as $area) {
+      foreach ($this->{$area} as $handler) {
+        $handler->preRender($this->result);
+      }
+    }
+
+    // Let modules modify the view just prior to rendering it.
+    $module_handler->invokeAll('views_pre_render', [$this]);
+
+    // Let the themes play too, because pre render is a very themey thing.
+    foreach ($themes as $theme_name) {
+      $function = $theme_name . '_views_pre_render';
+      if (function_exists($function)) {
+        $function($this);
+      }
+    }
+
+    $this->display_handler->output = $this->display_handler->render();
+
+    $exposed_form->postRender($this->display_handler->output);
+
+    $cache->postRender($this->display_handler->output);
+
+    // Let modules modify the view output after it is rendered.
+    $module_handler->invokeAll('views_post_render', [$this, &$this->display_handler->output, $cache]);
+
+    // Let the themes play too, because post render is a very themey thing.
+    foreach ($themes as $theme_name) {
+      $function = $theme_name . '_views_post_render';
+      if (function_exists($function)) {
+        $function($this, $this->display_handler->output, $cache);
+      }
+    }
+
+    return $this->display_handler->output;
+  }
+
+  /**
+   * Gets the cache tags associated with the executed view.
+   *
+   * Note: The cache plugin controls the used tags, so you can override it, if
+   *   needed.
+   *
+   * @return string[]
+   *   An array of cache tags.
+   */
+  public function getCacheTags() {
+    $this->initDisplay();
+    /** @var \Drupal\views\Plugin\views\cache\CachePluginBase $cache */
+    $cache = $this->display_handler->getPlugin('cache');
+    return $cache->getCacheTags();
+  }
+
+  /**
+   * Builds the render array outline for the given display.
+   *
+   * This render array has a #pre_render callback which will call
+   * ::executeDisplay in order to actually execute the view and then build the
+   * final render array structure.
+   *
+   * @param string $display_id
+   *   The display ID.
+   * @param array $args
+   *   An array of arguments passed along to the view.
+   * @param bool $cache
+   *   (optional) Should the result be render cached.
+   *
+   * @return array|null
+   *   A renderable array with #type 'view' or NULL if the display ID was
+   *   invalid.
+   */
+  public function buildRenderable($display_id = NULL, $args = [], $cache = TRUE) {
+    // @todo Extract that into a generic method.
+    if (empty($this->current_display) || $this->current_display != $this->chooseDisplay($display_id)) {
+      if (!$this->setDisplay($display_id)) {
+        return NULL;
+      }
+    }
+
+    return $this->display_handler->buildRenderable($args, $cache);
+  }
+
+  /**
+   * Executes the given display, with the given arguments.
+   *
+   * To be called externally by whatever mechanism invokes the view,
+   * such as a page callback, hook_block, etc.
+   *
+   * This function should NOT be used by anything external as this
+   * returns data in the format specified by the display. It can also
+   * have other side effects that are only intended for the 'proper'
+   * use of the display, such as setting page titles.
+   *
+   * If you simply want to view the display, use View::preview() instead.
+   *
+   * @param string $display_id
+   *   The display ID of the view to be executed.
+   * @param string[] $args
+   *   The arguments to be passed to the view.
+   *
+   * @return array|null
+   *   A renderable array containing the view output or NULL if the display ID
+   *   of the view to be executed doesn't exist.
+   */
+  public function executeDisplay($display_id = NULL, $args = []) {
+    if (empty($this->current_display) || $this->current_display != $this->chooseDisplay($display_id)) {
+      if (!$this->setDisplay($display_id)) {
+        return NULL;
+      }
+    }
+
+    $this->preExecute($args);
+
+    // Execute the view
+    $output = $this->display_handler->execute();
+
+    $this->postExecute();
+    return $output;
+  }
+
+  /**
+   * Previews the given display, with the given arguments.
+   *
+   * To be called externally, probably by an AJAX handler of some flavor.
+   * Can also be called when views are embedded, as this guarantees
+   * normalized output.
+   *
+   * This function does not do any access checks on the view. It is the
+   * responsibility of the caller to check $view->access() or implement other
+   * access logic. To render the view normally with access checks, use
+   * views_embed_view() instead.
+   *
+   * @return array|null
+   *   A renderable array containing the view output or NULL if the display ID
+   *   of the view to be executed doesn't exist.
+   */
+  public function preview($display_id = NULL, $args = []) {
+    if (empty($this->current_display) || ((!empty($display_id)) && $this->current_display != $display_id)) {
+      if (!$this->setDisplay($display_id)) {
+        return FALSE;
+      }
+    }
+
+    $this->preview = TRUE;
+    $this->preExecute($args);
+    // Preview the view.
+    $output = $this->display_handler->preview();
+
+    $this->postExecute();
+    return $output;
+  }
+
+  /**
+   * Runs attachments and lets the display do what it needs to before running.
+   *
+   * @param array $args
+   *   An array of arguments from the URL that can be used by the view.
+   */
+  public function preExecute($args = []) {
+    $this->old_view[] = views_get_current_view();
+    views_set_current_view($this);
+    $display_id = $this->current_display;
+
+    // Prepare the view with the information we have, but only if we were
+    // passed arguments, as they may have been set previously.
+    if ($args) {
+      $this->setArguments($args);
+    }
+
+    // Let modules modify the view just prior to executing it.
+    \Drupal::moduleHandler()->invokeAll('views_pre_view', [$this, $display_id, &$this->args]);
+
+    // Allow hook_views_pre_view() to set the dom_id, then ensure it is set.
+    $this->dom_id = !empty($this->dom_id) ? $this->dom_id : hash('sha256', $this->storage->id() . REQUEST_TIME . mt_rand());
+
+    // Allow the display handler to set up for execution
+    $this->display_handler->preExecute();
+  }
+
+  /**
+   * Unsets the current view, mostly.
+   */
+  public function postExecute() {
+    // unset current view so we can be properly destructed later on.
+    // Return the previous value in case we're an attachment.
+
+    if ($this->old_view) {
+      $old_view = array_pop($this->old_view);
+    }
+
+    views_set_current_view(isset($old_view) ? $old_view : FALSE);
+  }
+
+  /**
+   * Runs attachment displays for the view.
+   */
+  public function attachDisplays() {
+    if (!empty($this->is_attachment)) {
+      return;
+    }
+
+    if (!$this->display_handler->acceptAttachments()) {
+      return;
+    }
+
+    $this->is_attachment = TRUE;
+    // Find out which other displays attach to the current one.
+    foreach ($this->display_handler->getAttachedDisplays() as $id) {
+      $display_handler = $this->displayHandlers->get($id);
+      // Only attach enabled attachments.
+      if ($display_handler->isEnabled()) {
+        $cloned_view = Views::executableFactory()->get($this->storage);
+        $display_handler->attachTo($cloned_view, $this->current_display, $this->element);
+      }
+    }
+    $this->is_attachment = FALSE;
+  }
+
+  /**
+   * Determines if the given user has access to the view.
+   *
+   * Note that this sets the display handler if it hasn't been set.
+   *
+   * @param string $displays
+   *   The machine name of the display.
+   * @param \Drupal\Core\Session\AccountInterface $account
+   *   The user object.
+   *
+   * @return bool
+   *   TRUE if the user has access to the view, FALSE otherwise.
+   */
+  public function access($displays = NULL, $account = NULL) {
+    // No one should have access to disabled views.
+    if (!$this->storage->status()) {
+      return FALSE;
+    }
+
+    if (!isset($this->current_display)) {
+      $this->initDisplay();
+    }
+
+    if (!$account) {
+      $account = $this->user;
+    }
+
+    // We can't use choose_display() here because that function
+    // calls this one.
+    $displays = (array)$displays;
+    foreach ($displays as $display_id) {
+      if ($this->displayHandlers->has($display_id)) {
+        if (($display = $this->displayHandlers->get($display_id)) && $display->access($account)) {
+          return TRUE;
+        }
+      }
+    }
+
+    return FALSE;
+  }
+
+  /**
+   * Sets the used response object of the view.
+   *
+   * @param \Symfony\Component\HttpFoundation\Response $response
+   *   The response object which should be set.
+   */
+  public function setResponse(Response $response) {
+    $this->response = $response;
+  }
+
+  /**
+   * Gets the response object used by the view.
+   *
+   * @return \Symfony\Component\HttpFoundation\Response
+   *   The response object of the view.
+   */
+  public function getResponse() {
+    if (!isset($this->response)) {
+      $this->response = new Response();
+    }
+    return $this->response;
+  }
+
+  /**
+   * Sets the request object.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request object.
+   */
+  public function setRequest(Request $request) {
+    $this->request = $request;
+  }
+
+  /**
+   * Gets the request object.
+   *
+   * @return \Symfony\Component\HttpFoundation\Request
+   *   The request object.
+   */
+  public function getRequest() {
+    return $this->request;
+  }
+
+  /**
+   * Gets the view's current title.
+   *
+   * This can change depending upon how it was built.
+   *
+   * @return string|false
+   *   The view title, FALSE if the display is not set.
+   */
+  public function getTitle() {
+    if (empty($this->display_handler)) {
+      if (!$this->setDisplay('default')) {
+        return FALSE;
+      }
+    }
+
+    // During building, we might find a title override. If so, use it.
+    if (!empty($this->build_info['title'])) {
+      $title = $this->build_info['title'];
+    }
+    else {
+      $title = $this->display_handler->getOption('title');
+    }
+
+    // Allow substitutions from the first row.
+    if ($this->initStyle()) {
+      $title = $this->style_plugin->tokenizeValue($title, 0);
+    }
+    return $title;
+  }
+
+  /**
+   * Overrides the view's current title.
+   *
+   * The tokens in the title get's replaced before rendering.
+   *
+   * @return true
+   *   Always returns TRUE.
+   */
+  public function setTitle($title) {
+    $this->build_info['title'] = $title;
+    return TRUE;
+  }
+
+  /**
+   * Forces the view to build a title.
+   */
+  public function buildTitle() {
+    $this->initDisplay();
+
+    if (empty($this->built)) {
+      $this->initQuery();
+    }
+
+    $this->initHandlers();
+
+    $this->_buildArguments();
+  }
+
+  /**
+   * Determines whether you can link to the view or a particular display.
+   *
+   * Some displays (e.g. block displays) do not have their own route, but may
+   * optionally provide a link to another display that does have a route.
+   *
+   * @param array $args
+   *   (optional) The arguments.
+   * @param string $display_id
+   *   (optional) The display ID. The current display will be used by default.
+   *
+   * @return bool
+   *   TRUE if the current display has a valid route available, FALSE otherwise.
+   */
+  public function hasUrl($args = NULL, $display_id = NULL) {
+    if (!empty($this->override_url)) {
+      return TRUE;
+    }
+
+    // If the display has a valid route available (either its own or for a
+    // linked display), then we can provide a URL for it.
+    $display_handler = $this->displayHandlers->get($display_id ?: $this->current_display)->getRoutedDisplay();
+    if (!$display_handler instanceof DisplayRouterInterface) {
+      return FALSE;
+    }
+
+    // Look up the route name to make sure it exists.  The name may exist, but
+    // not be available yet in some instances when editing a view and doing
+    // a live preview.
+    $provider = \Drupal::service('router.route_provider');
+    try {
+      $provider->getRouteByName($display_handler->getRouteName());
+    }
+    catch (RouteNotFoundException $e) {
+      return FALSE;
+    }
+
+    return TRUE;
+  }
+
+  /**
+   * Gets the URL for the current view.
+   *
+   * This URL will be adjusted for arguments.
+   *
+   * @param array $args
+   *   (optional) Passed in arguments.
+   * @param string $display_id
+   *   (optional) Specify the display ID to link to, fallback to the current ID.
+   *
+   * @return \Drupal\Core\Url
+   *   The URL of the current view.
+   *
+   * @throws \InvalidArgumentException
+   *   Thrown when the current view doesn't have a route available.
+   */
+  public function getUrl($args = NULL, $display_id = NULL) {
+    if (!empty($this->override_url)) {
+      return $this->override_url;
+    }
+
+    $display_handler = $this->displayHandlers->get($display_id ?: $this->current_display)->getRoutedDisplay();
+    if (!$display_handler instanceof DisplayRouterInterface) {
+      throw new \InvalidArgumentException('You cannot create a URL to a display without routes.');
+    }
+
+    if (!isset($args)) {
+      $args = $this->args;
+
+      // Exclude arguments that were computed, not passed on the URL.
+      $position = 0;
+      if (!empty($this->argument)) {
+        foreach ($this->argument as $argument) {
+          if (!empty($argument->is_default) && !empty($argument->options['default_argument_skip_url'])) {
+            unset($args[$position]);
+          }
+          $position++;
+        }
+      }
+    }
+
+    $path = $this->getPath();
+
+    // Don't bother working if there's nothing to do:
+    if (empty($path) || (empty($args) && strpos($path, '%') === FALSE)) {
+      return $display_handler->getUrlInfo();
+    }
+
+    $argument_keys = isset($this->argument) ? array_keys($this->argument) : [];
+    $id = current($argument_keys);
+
+    /** @var \Drupal\Core\Url $url */
+    $url = $display_handler->getUrlInfo();
+    $route = $this->routeProvider->getRouteByName($url->getRouteName());
+
+    $variables = $route->compile()->getVariables();
+    $parameters = $url->getRouteParameters();
+
+    foreach ($variables as $variable_name) {
+      if (empty($args)) {
+        // Try to never put % in a URL; use the wildcard instead.
+        if ($id && !empty($this->argument[$id]->options['exception']['value'])) {
+          $parameters[$variable_name] = $this->argument[$id]->options['exception']['value'];
+        }
+        else {
+          // Provide some fallback in case no exception value could be found.
+          $parameters[$variable_name] = '*';
+        }
+      }
+      else {
+        $parameters[$variable_name] = array_shift($args);
+      }
+
+      if ($id) {
+        $id = next($argument_keys);
+      }
+    }
+
+    $url->setRouteParameters($parameters);
+    return $url;
+  }
+
+  /**
+   * Gets the Url object associated with the display handler.
+   *
+   * @param string $display_id
+   *   (optional) The display ID (used only to detail an exception).
+   *
+   * @return \Drupal\Core\Url
+   *   The display handlers URL object.
+   *
+   * @throws \InvalidArgumentException
+   *   Thrown when the display plugin does not have a URL to return.
+   */
+  public function getUrlInfo($display_id = '') {
+    $this->initDisplay();
+    if (!$this->display_handler instanceof DisplayRouterInterface) {
+      throw new \InvalidArgumentException("You cannot generate a URL for the display '$display_id'");
+    }
+    return $this->display_handler->getUrlInfo();
+  }
+
+  /**
+   * Gets the base path used for this view.
+   *
+   * @return string|false
+   *   The base path used for the view or FALSE if setting the display fails.
+   */
+  public function getPath() {
+    if (!empty($this->override_path)) {
+      return $this->override_path;
+    }
+
+    if (empty($this->display_handler)) {
+      if (!$this->setDisplay('default')) {
+        return FALSE;
+      }
+    }
+    return $this->display_handler->getPath();
+  }
+
+  /**
+   * Gets the current user.
+   *
+   * Views plugins can receive the current user in order to not need dependency
+   * injection.
+   *
+   * @return \Drupal\Core\Session\AccountInterface
+   *   The current user.
+   */
+  public function getUser() {
+    return $this->user;
+  }
+
+  /**
+   * Creates a duplicate ViewExecutable object.
+   *
+   * Makes a copy of this view that has been sanitized of handlers, any runtime
+   * data, ID, and UUID.
+   */
+  public function createDuplicate() {
+    return $this->storage->createDuplicate()->getExecutable();
+  }
+
+  /**
+   * Unsets references so that a $view object may be properly garbage collected.
+   */
+  public function destroy() {
+    foreach ($this::getHandlerTypes() as $type => $info) {
+      if (isset($this->$type)) {
+        foreach ($this->{$type} as $handler) {
+          $handler->destroy();
+        }
+      }
+    }
+
+    if (isset($this->style_plugin)) {
+      $this->style_plugin->destroy();
+    }
+
+    $reflection = new \ReflectionClass($this);
+    $defaults = $reflection->getDefaultProperties();
+    // The external dependencies should not be reset. This is not generated by
+    // the execution of a view.
+    unset(
+      $defaults['storage'],
+      $defaults['user'],
+      $defaults['request'],
+      $defaults['routeProvider'],
+      $defaults['viewsData']
+    );
+
+    foreach ($defaults as $property => $default) {
+      $this->{$property} = $default;
+    }
+  }
+
+  /**
+   * Makes sure the view is completely valid.
+   *
+   * @return array
+   *   An array of error strings. This will be empty if there are no validation
+   *   errors.
+   */
+  public function validate() {
+    $errors = [];
+
+    $this->initDisplay();
+    $current_display = $this->current_display;
+
+    foreach ($this->displayHandlers as $id => $display) {
+      if (!empty($display)) {
+        if (!empty($display->display['deleted'])) {
+          continue;
+        }
+
+        $result = $this->displayHandlers->get($id)->validate();
+        if (!empty($result) && is_array($result)) {
+          $errors[$id] = $result;
+        }
+      }
+    }
+
+    $this->setDisplay($current_display);
+
+    return $errors;
+  }
+
+  /**
+   * Provides a list of views handler types used in a view.
+   *
+   * This also provides some information about the views handler types.
+   *
+   * @return array
+   *   An array of associative arrays containing:
+   *   - title: The title of the handler type.
+   *   - ltitle: The lowercase title of the handler type.
+   *   - stitle: A singular title of the handler type.
+   *   - lstitle: A singular lowercase title of the handler type.
+   *   - plural: Plural version of the handler type.
+   *   - (optional) type: The actual internal used handler type. This key is
+   *     just used for header,footer,empty to link to the internal type: area.
+   */
+  public static function getHandlerTypes() {
+    return Views::getHandlerTypes();
+  }
+
+  /**
+   * Returns the valid types of plugins that can be used.
+   *
+   * @return array
+   *   An array of plugin type strings.
+   */
+  public static function getPluginTypes($type = NULL) {
+    return Views::getPluginTypes($type);
+  }
+
+  /**
+   * Adds an instance of a handler to the view.
+   *
+   * Items may be fields, filters, sort criteria, or arguments.
+   *
+   * @param string $display_id
+   *   The machine name of the display.
+   * @param string $type
+   *   The type of handler being added.
+   * @param string $table
+   *   The name of the table this handler is from.
+   * @param string $field
+   *   The name of the field this handler is from.
+   * @param array $options
+   *   (optional) Extra options for this instance. Defaults to an empty array.
+   * @param string $id
+   *   (optional) A unique ID for this handler instance. Defaults to NULL, in
+   *   which case one will be generated.
+   *
+   * @return string
+   *   The unique ID for this handler instance.
+   */
+  public function addHandler($display_id, $type, $table, $field, $options = [], $id = NULL) {
+    $types = $this::getHandlerTypes();
+    $this->setDisplay($display_id);
+
+    $data = $this->viewsData->get($table);
+    $fields = $this->displayHandlers->get($display_id)->getOption($types[$type]['plural']);
+
+    if (empty($id)) {
+      $id = $this->generateHandlerId($field, $fields);
+    }
+
+    // If the desired type is not found, use the original value directly.
+    $handler_type = !empty($types[$type]['type']) ? $types[$type]['type'] : $type;
+
+    $fields[$id] = [
+      'id' => $id,
+      'table' => $table,
+      'field' => $field,
+    ] + $options;
+
+    if (isset($data['table']['entity type'])) {
+      $fields[$id]['entity_type'] = $data['table']['entity type'];
+    }
+    if (isset($data[$field]['entity field'])) {
+      $fields[$id]['entity_field'] = $data[$field]['entity field'];
+    }
+
+    // Load the plugin ID if available.
+    if (isset($data[$field][$handler_type]['id'])) {
+      $fields[$id]['plugin_id'] = $data[$field][$handler_type]['id'];
+    }
+
+    $this->displayHandlers->get($display_id)->setOption($types[$type]['plural'], $fields);
+
+    return $id;
+  }
+
+  /**
+   * Generates a unique ID for an handler instance.
+   *
+   * These handler instances are typically fields, filters, sort criteria, or
+   * arguments.
+   *
+   * @param string $requested_id
+   *   The requested ID for the handler instance.
+   * @param array $existing_items
+   *   An array of existing handler instances, keyed by their IDs.
+   *
+   * @return string
+   *   A unique ID. This will be equal to $requested_id if no handler instance
+   *   with that ID already exists. Otherwise, it will be appended with an
+   *   integer to make it unique, e.g., "{$requested_id}_1",
+   *   "{$requested_id}_2", etc.
+   */
+  public static function generateHandlerId($requested_id, $existing_items) {
+    $count = 0;
+    $id = $requested_id;
+    while (!empty($existing_items[$id])) {
+      $id = $requested_id . '_' . ++$count;
+    }
+    return $id;
+  }
+
+  /**
+   * Gets an array of handler instances for the current display.
+   *
+   * @param string $type
+   *   The type of handlers to retrieve.
+   * @param string $display_id
+   *   (optional) A specific display machine name to use. If NULL, the current
+   *   display will be used.
+   *
+   * @return array
+   *   An array of handler instances of a given type for this display.
+   */
+  public function getHandlers($type, $display_id = NULL) {
+    $old_display_id = !empty($this->current_display) ? $this->current_display : 'default';
+
+    $this->setDisplay($display_id);
+
+    if (!isset($display_id)) {
+      $display_id = $this->current_display;
+    }
+
+    // Get info about the types so we can get the right data.
+    $types = static::getHandlerTypes();
+
+    $handlers = $this->displayHandlers->get($display_id)->getOption($types[$type]['plural']);
+
+    // Restore initial display id (if any) or set to 'default'.
+    if ($display_id != $old_display_id) {
+      $this->setDisplay($old_display_id);
+    }
+    return $handlers;
+  }
+
+  /**
+   * Gets the configuration of a handler instance on a given display.
+   *
+   * @param string $display_id
+   *   The machine name of the display.
+   * @param string $type
+   *   The type of handler to retrieve.
+   * @param string $id
+   *   The ID of the handler to retrieve.
+   *
+   * @return array|null
+   *   Either the handler instance's configuration, or NULL if the handler is
+   *   not used on the display.
+   */
+  public function getHandler($display_id, $type, $id) {
+    // Get info about the types so we can get the right data.
+    $types = static::getHandlerTypes();
+    // Initialize the display
+    $this->setDisplay($display_id);
+
+    // Get the existing configuration
+    $fields = $this->displayHandlers->get($display_id)->getOption($types[$type]['plural']);
+
+    return isset($fields[$id]) ? $fields[$id] : NULL;
+  }
+
+  /**
+   * Sets the configuration of a handler instance on a given display.
+   *
+   * @param string $display_id
+   *   The machine name of the display.
+   * @param string $type
+   *   The type of handler being set.
+   * @param string $id
+   *   The ID of the handler being set.
+   * @param array|null $item
+   *   An array of configuration for a handler, or NULL to remove this instance.
+   *
+   * @see set_item_option()
+   */
+  public function setHandler($display_id, $type, $id, $item) {
+    // Get info about the types so we can get the right data.
+    $types = static::getHandlerTypes();
+    // Initialize the display.
+    $this->setDisplay($display_id);
+
+    // Get the existing configuration.
+    $fields = $this->displayHandlers->get($display_id)->getOption($types[$type]['plural']);
+    if (isset($item)) {
+      $fields[$id] = $item;
+    }
+
+    // Store.
+    $this->displayHandlers->get($display_id)->setOption($types[$type]['plural'], $fields);
+  }
+
+  /**
+   * Removes configuration for a handler instance on a given display.
+   *
+   * @param string $display_id
+   *   The machine name of the display.
+   * @param string $type
+   *   The type of handler being removed.
+   * @param string $id
+   *   The ID of the handler being removed.
+   */
+  public function removeHandler($display_id, $type, $id) {
+    // Get info about the types so we can get the right data.
+    $types = static::getHandlerTypes();
+    // Initialize the display.
+    $this->setDisplay($display_id);
+
+    // Get the existing configuration.
+    $fields = $this->displayHandlers->get($display_id)->getOption($types[$type]['plural']);
+    // Unset the item.
+    unset($fields[$id]);
+
+    // Store.
+    $this->displayHandlers->get($display_id)->setOption($types[$type]['plural'], $fields);
+  }
+
+  /**
+   * Sets an option on a handler instance.
+   *
+   * Use this only if you have just 1 or 2 options to set; if you have many,
+   * consider getting the handler instance, adding the options and using
+   * set_item() directly.
+   *
+   * @param string $display_id
+   *   The machine name of the display.
+   * @param string $type
+   *   The type of handler being set.
+   * @param string $id
+   *   The ID of the handler being set.
+   * @param string $option
+   *   The configuration key for the value being set.
+   * @param mixed $value
+   *   The value being set.
+   *
+   * @see set_item()
+   */
+  public function setHandlerOption($display_id, $type, $id, $option, $value) {
+    $item = $this->getHandler($display_id, $type, $id);
+    $item[$option] = $value;
+    $this->setHandler($display_id, $type, $id, $item);
+  }
+
+  /**
+   * Enables admin links on the rendered view.
+   *
+   * @param bool $show_admin_links
+   *   TRUE if the admin links should be shown.
+   */
+  public function setShowAdminLinks($show_admin_links) {
+    $this->showAdminLinks = (bool) $show_admin_links;
+  }
+
+  /**
+   * Returns whether admin links should be rendered on the view.
+   *
+   * @return bool
+   *   TRUE if admin links should be rendered, else FALSE.
+   */
+  public function getShowAdminLinks() {
+    if (!isset($this->showAdminLinks)) {
+      return $this->getDisplay()->getOption('show_admin_links');
+    }
+    return $this->showAdminLinks;
+  }
+
+  /**
+   * Merges all plugin default values for each display.
+   */
+  public function mergeDefaults() {
+    $this->initDisplay();
+    // Initialize displays and merge all plugin defaults.
+    foreach ($this->displayHandlers as $display) {
+      $display->mergeDefaults();
+    }
+  }
+
+  /**
+   * Provides a full array of possible theme functions to try for a given hook.
+   *
+   * @param string $hook
+   *   The hook to use. This is the base theme/template name.
+   *
+   * @return array
+   *   An array of theme hook suggestions.
+   */
+  public function buildThemeFunctions($hook) {
+    $themes = [];
+    $display = isset($this->display_handler) ? $this->display_handler->display : NULL;
+    $id = $this->storage->id();
+
+    if ($display) {
+      $themes[] = $hook . '__' . $id . '__' . $display['id'];
+      $themes[] = $hook . '__' . $display['id'];
+      // Add theme suggestions for each single tag.
+      foreach (Tags::explode($this->storage->get('tag')) as $tag) {
+        $themes[] = $hook . '__' . preg_replace('/[^a-z0-9]/', '_', strtolower($tag));
+      }
+
+      if ($display['id'] != $display['display_plugin']) {
+        $themes[] = $hook . '__' . $id . '__' . $display['display_plugin'];
+        $themes[] = $hook . '__' . $display['display_plugin'];
+      }
+    }
+    $themes[] = $hook . '__' . $id;
+    $themes[] = $hook;
+
+    return $themes;
+  }
+
+  /**
+   * Determines if this view has form elements.
+   *
+   * @return bool
+   *   TRUE if this view contains handlers with views form implementations,
+   *   FALSE otherwise.
+   */
+  public function hasFormElements() {
+    foreach ($this->field as $field) {
+      if (property_exists($field, 'views_form_callback') || method_exists($field, 'viewsForm')) {
+        return TRUE;
+      }
+    }
+    $area_handlers = array_merge(array_values($this->header), array_values($this->footer));
+    $empty = empty($this->result);
+    foreach ($area_handlers as $area) {
+      if (method_exists($area, 'viewsForm') && !$area->viewsFormEmpty($empty)) {
+        return TRUE;
+      }
+    }
+
+    return FALSE;
+  }
+
+  /**
+   * Gets dependencies for the view.
+   *
+   * @see \Drupal\views\Entity\View::calculateDependencies()
+   * @see \Drupal\views\Entity\View::getDependencies()
+   *
+   * @return array
+   *   An array of dependencies grouped by type (module, theme, entity).
+   */
+  public function getDependencies() {
+    return $this->storage->calculateDependencies()->getDependencies();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function serialize() {
+    return serialize([
+      // Only serialize the storage entity ID.
+      $this->storage->id(),
+      $this->current_display,
+      $this->args,
+      $this->current_page,
+      $this->exposed_input,
+      $this->exposed_raw_input,
+      $this->exposed_data,
+      $this->dom_id,
+      $this->executed,
+    ]);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function unserialize($serialized) {
+    list($storage, $current_display, $args, $current_page, $exposed_input, $exposed_raw_input, $exposed_data, $dom_id, $executed) = unserialize($serialized);
+
+    // There are cases, like in testing, where we don't have a container
+    // available.
+    if (\Drupal::hasContainer()) {
+      $this->setRequest(\Drupal::request());
+      $this->user = \Drupal::currentUser();
+
+      $this->storage = \Drupal::entityManager()->getStorage('view')->load($storage);
+
+      $this->setDisplay($current_display);
+      $this->setArguments($args);
+      $this->setCurrentPage($current_page);
+      $this->setExposedInput($exposed_input);
+      $this->exposed_data = $exposed_data;
+      $this->exposed_raw_input = $exposed_raw_input;
+      $this->dom_id = $dom_id;
+
+      $this->initHandlers();
+
+      // If the display was previously executed, execute it now.
+      if ($executed) {
+        $this->execute($this->current_display);
+      }
+    }
+  }
+
+}