Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/lib/Drupal/Core/Block/BlockBase.php

@@ -9,13 +9,12 @@ namespace Drupal\Core\Block;
 
 use Drupal\block\BlockInterface;
 use Drupal\Core\Access\AccessResult;
-use Drupal\Core\Cache\CacheableDependencyInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Plugin\ContextAwarePluginAssignmentTrait;
 use Drupal\Core\Plugin\ContextAwarePluginBase;
 use Drupal\Component\Utility\Unicode;
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Language\LanguageInterface;
-use Drupal\Core\Cache\Cache;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Component\Transliteration\TransliterationInterface;
 
@@ -30,6 +29,8 @@ use Drupal\Component\Transliteration\TransliterationInterface;
  */
 abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginInterface {
 
+  use ContextAwarePluginAssignmentTrait;
+
   /**
    * The transliteration service.
    *
@@ -47,7 +48,7 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
 
     $definition = $this->getPluginDefinition();
     // Cast the admin label to a string since it is an object.
-    // @see \Drupal\Core\StringTranslation\TranslationWrapper
+    // @see \Drupal\Core\StringTranslation\TranslatableMarkup
     return (string) $definition['admin_label'];
   }
 
@@ -89,10 +90,6 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
       'label' => '',
       'provider' => $this->pluginDefinition['provider'],
       'label_display' => BlockInterface::BLOCK_LABEL_VISIBLE,
-      'cache' => array(
-        // Blocks are cacheable by default.
-        'max_age' => Cache::PERMANENT,
-      ),
     );
   }
 
@@ -180,24 +177,10 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
       '#default_value' => ($this->configuration['label_display'] === BlockInterface::BLOCK_LABEL_VISIBLE),
       '#return_value' => BlockInterface::BLOCK_LABEL_VISIBLE,
     );
-    // Identical options to the ones for page caching.
-    // @see \Drupal\system\Form\PerformanceForm::buildForm()
-    $period = array(0, 60, 180, 300, 600, 900, 1800, 2700, 3600, 10800, 21600, 32400, 43200, 86400);
-    $period = array_map(array(\Drupal::service('date.formatter'), 'formatInterval'), array_combine($period, $period));
-    $period[0] = '<' . $this->t('no caching') . '>';
-    $period[\Drupal\Core\Cache\Cache::PERMANENT] = $this->t('Forever');
-    $form['cache'] = array(
-      '#type' => 'details',
-      '#title' => $this->t('Cache settings'),
-    );
-    $form['cache']['max_age'] = array(
-      '#type' => 'select',
-      '#title' => $this->t('Maximum age'),
-      '#description' => $this->t('The maximum time this block may be cached.'),
-      '#default_value' => $this->configuration['cache']['max_age'],
-      '#options' => $period,
-    );
 
+    // Add context mapping UI form elements.
+    $contexts = $form_state->getTemporaryValue('gathered_contexts') ?: [];
+    $form['context_mapping'] = $this->addContextAssignmentElement($this, $contexts);
     // Add plugin-specific settings for this block type.
     $form += $this->blockForm($form, $form_state);
     return $form;
@@ -244,7 +227,6 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
       $this->configuration['label'] = $form_state->getValue('label');
       $this->configuration['label_display'] = $form_state->getValue('label_display');
       $this->configuration['provider'] = $form_state->getValue('provider');
-      $this->configuration['cache'] = $form_state->getValue('cache');
       $this->blockSubmit($form, $form_state);
     }
   }
@@ -272,16 +254,6 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
     return $transliterated;
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function getCacheMaxAge() {
-    $max_age = parent::getCacheMaxAge();
-    // @todo Configurability of this will be removed in
-    //   https://www.drupal.org/node/2458763.
-    return Cache::mergeMaxAges($max_age, (int) $this->configuration['cache']['max_age']);
-  }
-
   /**
    * Wraps the transliteration service.
    *

core/lib/Drupal/Core/Block/MainContentBlockPluginInterface.php

@@ -10,7 +10,7 @@ namespace Drupal\Core\Block;
 /**
  * The interface for "main page content" blocks.
  *
- * A main page content block represents the content returns by the controller.
+ * A main page content block represents the content returned by the controller.
  *
  * @ingroup block_api
  */

core/lib/Drupal/Core/Block/Plugin/Block/PageTitleBlock.php

@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Plugin\Block\PageTitleBlock.
+ */
+
+namespace Drupal\Core\Block\Plugin\Block;
+
+use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Block\TitleBlockPluginInterface;
+
+/**
+ * Provides a block to display the page title.
+ *
+ * @Block(
+ *   id = "page_title_block",
+ *   admin_label = @Translation("Page title"),
+ * )
+ */
+class PageTitleBlock extends BlockBase implements TitleBlockPluginInterface {
+
+  /**
+   * The page title: a string (plain title) or a render array (formatted title).
+   *
+   * @var string|array
+   */
+  protected $title = '';
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setTitle($title) {
+    $this->title = $title;
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function defaultConfiguration() {
+    return ['label_display' => FALSE];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+    return [
+      '#type' => 'page_title',
+      '#title' => $this->title,
+    ];
+  }
+
+}

core/lib/Drupal/Core/Block/TitleBlockPluginInterface.php

@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Block\TitleBlockPluginInterface.
+ */
+
+namespace Drupal\Core\Block;
+
+/**
+ * The interface for "title" blocks.
+ *
+ * A title block shows the title returned by the controller.
+ *
+ * @ingroup block_api
+ *
+ * @see \Drupal\Core\Render\Element\PageTitle
+ */
+interface TitleBlockPluginInterface extends BlockPluginInterface {
+
+  /**
+   * Sets the title.
+   *
+   * @param string|array $title
+   *   The page title: either a string for plain titles or a render array for
+   *   formatted titles.
+   */
+  public function setTitle($title);
+
+}