diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
index 4c2df27..d281731 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorCategoryBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides an 'Aggregator category' block for the latest items in a category.
@@ -64,7 +65,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $id = $this->getPluginId();
     if ($category = db_query('SELECT cid, title, block FROM {aggregator_category} WHERE cid = :cid', array(':cid' => $id))->fetchObject()) {
       $result = db_query_range('SELECT i.* FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON ci.iid = i.iid WHERE ci.cid = :cid ORDER BY i.timestamp DESC, i.iid DESC', 0, $this->configuration['block_count'], array(':cid' => $category->cid));
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
index e902eb5..528c7db 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/block/block/AggregatorFeedBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides an 'Aggregator feed' block with the latest items from the feed.
@@ -64,7 +65,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     // Plugin IDs look something like this: aggregator_feed_block:1.
     list(, $id) = explode(':', $this->getPluginId());
     if ($feed = db_query('SELECT fid, title, block FROM {aggregator_feed} WHERE block <> 0 AND fid = :fid', array(':fid' => $id))->fetchObject()) {
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php
index 6f7be2e..e09a3ab 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php
@@ -9,6 +9,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Defines a generic custom block type.
@@ -107,7 +108,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     // Populate the block with the user-defined block body.
     return array(
       '#theme' => 'custom_block_block',
diff --git a/core/modules/block/lib/Drupal/block/BlockBase.php b/core/modules/block/lib/Drupal/block/BlockBase.php
index b9a149f..4e29b74 100644
--- a/core/modules/block/lib/Drupal/block/BlockBase.php
+++ b/core/modules/block/lib/Drupal/block/BlockBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\block;
 
 use Drupal\Component\Plugin\PluginBase;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Defines a base block implementation that most blocks plugins will extend.
diff --git a/core/modules/block/lib/Drupal/block/BlockFormController.php b/core/modules/block/lib/Drupal/block/BlockFormController.php
index 3d2d29b..305261c 100644
--- a/core/modules/block/lib/Drupal/block/BlockFormController.php
+++ b/core/modules/block/lib/Drupal/block/BlockFormController.php
@@ -36,7 +36,7 @@ public function form(array $form, array &$form_state, EntityInterface $entity) {
       '#type' => 'textfield',
       '#title' => t('Block title'),
       '#maxlength' => 255,
-      '#default_value' => $entity->label(),
+      '#default_value' => !$entity->isNew() ? $entity->label() : $definition['subject'],
     );
     $form['settings']['machine_name'] = array(
       '#type' => 'textfield',
diff --git a/core/modules/block/lib/Drupal/block/BlockInterface.php b/core/modules/block/lib/Drupal/block/BlockInterface.php
index 602efce..7946716 100644
--- a/core/modules/block/lib/Drupal/block/BlockInterface.php
+++ b/core/modules/block/lib/Drupal/block/BlockInterface.php
@@ -6,6 +6,8 @@
 
 namespace Drupal\block;
 
+use Drupal\block\Plugin\Core\Entity\Block;
+
 /**
  * Defines the required interface for all block plugins.
  *
@@ -31,11 +33,14 @@
   public function blockSettings();
 
   /**
-   * Builds and returns the renderable array for this block.
+   * Builds and returns the renderable array for this block plugin.
+   *
+   * @param \Drupal\block\Plugin\Core\Entity\Block $entity
+   *   The block entity containing this plugin.
    *
    * @return array
-   *   A renderable array representing the output of the block.
+   *   A renderable array representing the content of the block.
    */
-  public function blockBuild();
+  public function blockBuild(Block $entity);
 
 }
diff --git a/core/modules/block/lib/Drupal/block/BlockRenderController.php b/core/modules/block/lib/Drupal/block/BlockRenderController.php
index 4ecb2a1..ef373d6 100644
--- a/core/modules/block/lib/Drupal/block/BlockRenderController.php
+++ b/core/modules/block/lib/Drupal/block/BlockRenderController.php
@@ -45,7 +45,7 @@ protected function getBuildDefaults(EntityInterface $entity, $view_mode, $langco
       return array();
     }
 
-    $defaults = array(
+    return array(
       '#block' => $entity,
       '#weight' => $entity->get('weight'),
       '#theme_wrappers' => array('block'),
@@ -53,19 +53,9 @@ protected function getBuildDefaults(EntityInterface $entity, $view_mode, $langco
         'id' => $entity->get('plugin'),
         'region' => $entity->get('region'),
         'module' => $entity->get('module'),
+        'subject' => $entity->label(),
       ),
     );
-    $defaults['#block_config'] += $entity->getPlugin()->getConfig();
-
-    // @todo This is a hold-over from the old behavior, it is crazy.
-    if (!empty($defaults['#block_config']['label'])) {
-      $defaults['#block_config']['subject'] = $defaults['#block_config']['label'];
-    }
-    elseif ($label = $entity->label()) {
-      $defaults['#block_config']['subject'] = $label;
-    }
-
-    return $defaults;
   }
 
   /**
@@ -82,7 +72,7 @@ public function view(EntityInterface $entity, $view_mode = 'full', $langcode = N
   public function viewMultiple(array $entities = array(), $view_mode = 'full', $langcode = NULL) {
     $build = array();
     foreach ($entities as $entity_id => $entity) {
-      $build[$entity_id] = $entity->getPlugin()->blockBuild();
+      $build[$entity_id] = $entity->getPlugin()->blockBuild($entity);
       // Allow blocks to be empty, do not add in the defaults.
       if (!empty($build[$entity_id])) {
         $build[$entity_id] = $this->getBuildDefaults($entity, $view_mode, $langcode) + $build[$entity_id];
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
index b1cc516..ad1229a 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
@@ -8,7 +8,7 @@
 namespace Drupal\block\Tests;
 
 use Drupal\simpletest\DrupalUnitTestBase;
-use Drupal\system\Plugin\block\block\SystemPoweredByBlock;
+use Drupal\block_test\Plugin\block\block\TestHtmlIdBlock;
 use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\block\BlockStorageController;
 use Drupal\Core\Entity\EntityMalformedException;
@@ -26,7 +26,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
    *
    * @var array
    */
-  public static $modules = array('system');
+  public static $modules = array('block_test');
 
   /**
    * The block storage controller.
@@ -78,44 +78,44 @@ protected function createTests() {
 
     // Create a block with only required values.
     $entity = $this->controller->create(array(
-      'id' => 'stark.powered',
-      'plugin' => 'system_powered_by_block',
+      'id' => 'stark.test_block',
+      'plugin' => 'test_html_id',
     ));
     $entity->save();
 
     $this->assertTrue($entity instanceof Block, 'The newly created entity is a Block.');
 
     // Verify all of the block properties.
-    $actual_properties = config('plugin.core.block.stark.powered')->get();
+    $actual_properties = config('plugin.core.block.stark.test_block')->get();
     $this->assertTrue(!empty($actual_properties['uuid']), 'The block UUID is set.');
     unset($actual_properties['uuid']);
 
     // Ensure that default values are filled in.
     $expected_properties = array(
-      'id' => 'stark.powered',
+      'id' => 'stark.test_block',
       'label' => '',
       'region' => '-1',
       'weight' => '',
-      'cache' => '-1',
-      'module' => 'system',
+      'cache' => '1',
+      'module' => 'block_test',
       'theme' => 'stark',
       'status' => '1',
       'visibility' => array(),
-      'plugin' => 'system_powered_by_block',
+      'plugin' => 'test_html_id',
       'configuration' => array(
-        'subject' => t('Powered by Drupal'),
+        'subject' => t('Test block html id'),
       ),
     );
     $this->assertIdentical($actual_properties, $expected_properties, 'The block properties are exported correctly.');
 
-    $this->assertTrue($entity->getPlugin() instanceof SystemPoweredByBlock, 'The entity has an instance of the correct block plugin.');
+    $this->assertTrue($entity->getPlugin() instanceof TestHtmlIdBlock, 'The entity has an instance of the correct block plugin.');
   }
 
   /**
    * Tests the rendering of blocks.
    */
   protected function loadTests() {
-    $entities = $this->controller->load(array('stark.powered'));
+    $entities = $this->controller->load(array('stark.test_block'));
     $entity = reset($entities);
 
     $this->assertTrue($entity instanceof Block, 'The loaded entity is a Block.');
@@ -124,7 +124,7 @@ protected function loadTests() {
     $this->assertEqual($entity->get('region'), '-1');
     $this->assertTrue($entity->get('status'));
     $this->assertEqual($entity->get('theme'), 'stark');
-    $this->assertEqual($entity->get('module'), 'system');
+    $this->assertEqual($entity->get('module'), 'block_test');
     $this->assertTrue($entity->uuid());
   }
 
@@ -133,23 +133,23 @@ protected function loadTests() {
    */
   protected function renderTests() {
     $entity = $this->controller->create(array(
-      'id' => 'stark.powered',
-      'plugin' => 'system_powered_by_block',
+      'id' => 'stark.test_block',
+      'plugin' => 'test_html_id',
     ));
 
     // Test the rendering of a block.
     $output = entity_view($entity, 'block');
     $expected = array();
-    $expected[] = '  <div id="block-powered"  class="block block-system">';
+    $expected[] = '  <div id="block-test-block"  class="block block-block-test">';
     $expected[] = '';
-    $expected[] = '    <h2 class="">Powered by Drupal</h2>';
+    $expected[] = '    <h2 class="">Test block html id</h2>';
     $expected[] = '  ';
     $expected[] = '  <div class="content">';
-    $expected[] = '    <span>Powered by <a href="http://drupal.org">Drupal</a></span>  </div>';
+    $expected[] = '      </div>';
     $expected[] = '</div>';
     $expected[] = '';
     $expected_output = implode("\n", $expected);
-    $this->assertEqual(render($output), $expected_output, 'The block rendered correctly.');
+    $this->assertEqual(drupal_render($output), $expected_output, 'The block rendered correctly.');
 
     // Reset the HTML IDs so that the next render is not affected.
     drupal_static_reset('drupal_html_id');
@@ -158,23 +158,23 @@ protected function renderTests() {
     $entity->set('label', 'Powered by Bananas');
     $output = entity_view($entity, 'block');
     $expected = array();
-    $expected[] = '  <div id="block-powered"  class="block block-system">';
+    $expected[] = '  <div id="block-test-block"  class="block block-block-test">';
     $expected[] = '';
     $expected[] = '    <h2 class="">Powered by Bananas</h2>';
     $expected[] = '  ';
     $expected[] = '  <div class="content">';
-    $expected[] = '    <span>Powered by <a href="http://drupal.org">Drupal</a></span>  </div>';
+    $expected[] = '      </div>';
     $expected[] = '</div>';
     $expected[] = '';
     $expected_output = implode("\n", $expected);
-    $this->assertEqual(render($output), $expected_output, 'The block rendered correctly.');
+    $this->assertEqual(drupal_render($output), $expected_output, 'The block rendered correctly.');
   }
 
   /**
    * Tests the deleting of blocks.
    */
   protected function deleteTests() {
-    $entities = $this->controller->load(array('stark.powered'));
+    $entities = $this->controller->load(array('stark.test_block'));
     $entity = reset($entities);
 
     // Ensure that the storage isn't currently empty.
@@ -197,12 +197,12 @@ public function testDefaultBlocks() {
     $entities = $this->controller->load();
     $this->assertTrue(empty($entities), 'There are no blocks initially.');
 
-    // Enable the Help module, which provides a default block.
-    $this->enableModules(array('help'));
+    // Install the block_test.module, so that its default config is installed.
+    $this->enableModules(array('block_test'));
 
     $entities = $this->controller->load();
     $entity = reset($entities);
-    $this->assertEqual($entity->id(), 'seven.help', 'The default help block was loaded.');
+    $this->assertEqual($entity->id(), 'stark.test_block', 'The default test block was loaded.');
   }
 
 }
diff --git a/core/modules/block/tests/config/plugin.core.block.stark.test_block.yml b/core/modules/block/tests/config/plugin.core.block.stark.test_block.yml
new file mode 100644
index 0000000..dacfb64
--- /dev/null
+++ b/core/modules/block/tests/config/plugin.core.block.stark.test_block.yml
@@ -0,0 +1,13 @@
+id: stark.test_block
+label: ''
+uuid: 6dcd7278-40c5-426a-9804-4fd859748a30
+region: '-1'
+weight: ''
+cache: '1'
+module: block_test
+theme: stark
+status: '1'
+visibility: {  }
+plugin: test_html_id
+configuration:
+  subject: 'Test block html id'
diff --git a/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php b/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
index aeb7709..5f7b980 100644
--- a/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
+++ b/core/modules/block/tests/lib/Drupal/block_test/Plugin/block/block/TestCacheBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a block to test caching.
@@ -36,7 +37,7 @@ public function blockSettings() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       '#children' => state()->get('block_test.content'),
     );
diff --git a/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php b/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
index c1823e1..1f43782 100644
--- a/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
+++ b/core/modules/book/lib/Drupal/book/Plugin/block/block/BookNavigationBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Book navigation' block.
@@ -61,7 +62,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $current_bid = 0;
     if ($node = menu_get_object()) {
       $current_bid = empty($node->book['bid']) ? 0 : $node->book['bid'];
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php b/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
index d5c3d7b..77114fe 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/block/block/RecentCommentsBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Recent comments' block.
@@ -61,7 +62,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       '#theme' => 'comment_block',
       '#number' => $this->configuration['block_count'],
diff --git a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
index afa7117..7ac7010 100644
--- a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
+++ b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/ActiveTopicsBlock.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides an 'Active forum topics' block.
@@ -24,7 +25,7 @@ class ActiveTopicsBlock extends ForumBlockBase {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $query = db_select('forum_index', 'f')
       ->fields('f')
       ->addTag('node_access')
diff --git a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
index 083469c..2cfcb8b 100644
--- a/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
+++ b/core/modules/forum/lib/Drupal/forum/Plugin/block/block/NewTopicsBlock.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'New forum topics' block.
@@ -24,7 +25,7 @@ class NewTopicsBlock extends ForumBlockBase {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $query = db_select('forum_index', 'f')
       ->fields('f')
       ->addTag('node_access')
diff --git a/core/modules/help/config/plugin.core.block.seven.help.yml b/core/modules/help/config/plugin.core.block.seven.help.yml
deleted file mode 100644
index f75e2d7..0000000
--- a/core/modules/help/config/plugin.core.block.seven.help.yml
+++ /dev/null
@@ -1,20 +0,0 @@
-id: seven.help
-label: ''
-region: help
-weight: ''
-cache: '-1'
-module: system
-theme: seven
-status: '1'
-visibility:
-  path:
-    visibility: '0'
-    pages: ''
-  role:
-    roles: {  }
-  node_type:
-    types:
-      article: '0'
-      page: '0'
-  visibility__active_tab: edit-visibility-path
-plugin: system_help_block
diff --git a/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php b/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
index a698695..89d6562 100644
--- a/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
+++ b/core/modules/language/lib/Drupal/language/Plugin/block/block/LanguageBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Language switcher' block.
@@ -33,7 +34,7 @@ function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $build = array();
     $path = drupal_is_front_page() ? '<front>' : current_path();
     list($plugin_id, $type) = explode(':', $this->getPluginId());
diff --git a/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php b/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
index 7134dc50..2924bee 100644
--- a/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
+++ b/core/modules/menu/lib/Drupal/menu/Plugin/block/block/MenuBlock.php
@@ -10,6 +10,7 @@
 use Drupal\system\Plugin\block\block\SystemMenuBlock;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a generic Menu block.
@@ -26,7 +27,7 @@ class MenuBlock extends SystemMenuBlock {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     list($plugin, $menu) = explode(':', $this->getPluginId());
     return menu_tree($menu);
   }
diff --git a/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php b/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
index cb05c5c..d9abc2d 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/block/block/RecentContentBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Recent content' block.
@@ -61,7 +62,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     if ($nodes = node_get_recent($this->configuration['block_count'])) {
       return array(
         '#theme' => 'node_recent_block',
diff --git a/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php b/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
index 5c83e27..b83d9f4 100644
--- a/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
+++ b/core/modules/node/lib/Drupal/node/Plugin/block/block/SyndicateBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Syndicate' block that links to the site's RSS feed.
@@ -41,7 +42,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       '#theme' => 'feed_icon',
       '#url' => 'rss.xml',
diff --git a/core/modules/poll/lib/Drupal/poll/Plugin/block/block/PollRecentBlock.php b/core/modules/poll/lib/Drupal/poll/Plugin/block/block/PollRecentBlock.php
index b597741..5b96e3b 100644
--- a/core/modules/poll/lib/Drupal/poll/Plugin/block/block/PollRecentBlock.php
+++ b/core/modules/poll/lib/Drupal/poll/Plugin/block/block/PollRecentBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Most recent poll' block.
@@ -67,7 +68,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $poll = node_load($this->record);
     if ($poll->nid) {
       $poll = poll_block_latest_poll_view($poll);
diff --git a/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php b/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
index d9bdb7c..4cdc83f 100644
--- a/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
+++ b/core/modules/search/lib/Drupal/search/Plugin/block/block/SearchBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Search form' block.
@@ -32,7 +33,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(drupal_get_form('search_block_form'));
   }
 
diff --git a/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php b/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
index d236a19..818650b 100644
--- a/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
+++ b/core/modules/shortcut/lib/Drupal/shortcut/Plugin/block/block/ShortcutsBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Shortcut' block.
@@ -25,7 +26,7 @@ class ShortcutsBlock extends BlockBase {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       shortcut_renderable_links(shortcut_current_displayed_set()),
     );
diff --git a/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php b/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
index 8c9fdf6..3fc4099 100644
--- a/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
+++ b/core/modules/statistics/lib/Drupal/statistics/Plugin/block/block/StatisticsPopularBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Popular content' block.
@@ -118,7 +119,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $content = array();
 
     if ($this->day_list) {
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
index 6026f83..9b8d75c 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemHelpBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'System Help' block.
@@ -40,7 +41,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       '#children' => $this->help,
     );
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
index 8b40092..0c8a708 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMainBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Main page content' block.
@@ -25,7 +26,7 @@ class SystemMainBlock extends BlockBase {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       drupal_set_page_content()
     );
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
index 0307257..6087fa7 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemMenuBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'System Menu' block.
@@ -35,7 +36,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     list($plugin, $derivative) = explode(':', $this->getPluginId());
     // Derivatives are prefixed with 'menu-'.
     $menu = substr($derivative, 5);
diff --git a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
index b363725..7fe9d29 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/block/block/SystemPoweredByBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Powered by Drupal' block.
@@ -25,7 +26,7 @@ class SystemPoweredByBlock extends BlockBase {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     return array(
       '#children' => theme('system_powered_by'),
     );
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCrudHookTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCrudHookTest.php
index db722bb..22e6cb9 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCrudHookTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCrudHookTest.php
@@ -29,7 +29,7 @@ class EntityCrudHookTest extends WebTestBase {
    *
    * @var array
    */
-  public static $modules = array('entity_crud_hook_test', 'taxonomy', 'comment', 'file', 'entity_test');
+  public static $modules = array('entity_crud_hook_test', 'taxonomy', 'block_test', 'block', 'comment', 'file', 'entity_test');
 
   protected $ids = array();
 
@@ -67,6 +67,54 @@ protected function assertHookMessageOrder($messages) {
   }
 
   /**
+   * Tests hook invocations for CRUD operations on blocks.
+   */
+  public function testBlockHooks() {
+    $entity = entity_create('block', array(
+      'id' => 'stark.test_block',
+      'plugin' => 'test_html_id',
+    ));
+    $_SESSION['entity_crud_hook_test'] = array();
+    $entity->save();
+
+    $this->assertHookMessageOrder(array(
+      'entity_crud_hook_test_block_presave called',
+      'entity_crud_hook_test_entity_presave called for type block',
+      'entity_crud_hook_test_block_insert called',
+      'entity_crud_hook_test_entity_insert called for type block',
+    ));
+
+    $_SESSION['entity_crud_hook_test'] = array();
+    $entity = entity_load('block', $entity->id());
+
+    $this->assertHookMessageOrder(array(
+      'entity_crud_hook_test_entity_load called for type block',
+      'entity_crud_hook_test_block_load called',
+    ));
+
+    $_SESSION['entity_crud_hook_test'] = array();
+    $entity->label = 'New label';
+    $entity->save();
+
+    $this->assertHookMessageOrder(array(
+      'entity_crud_hook_test_block_presave called',
+      'entity_crud_hook_test_entity_presave called for type block',
+      'entity_crud_hook_test_block_update called',
+      'entity_crud_hook_test_entity_update called for type block',
+    ));
+
+    $_SESSION['entity_crud_hook_test'] = array();
+    $entity->delete();
+
+    $this->assertHookMessageOrder(array(
+      'entity_crud_hook_test_block_predelete called',
+      'entity_crud_hook_test_entity_predelete called for type block',
+      'entity_crud_hook_test_block_delete called',
+      'entity_crud_hook_test_entity_delete called for type block',
+    ));
+  }
+
+  /**
    * Tests hook invocations for CRUD operations on comments.
    */
   public function testCommentHooks() {
diff --git a/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.module b/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.module
index 8a1e43c..f2bb297 100644
--- a/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.module
+++ b/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.module
@@ -15,6 +15,13 @@ function entity_crud_hook_test_entity_presave(EntityInterface $entity) {
 }
 
 /**
+ * Implements hook_block_presave().
+ */
+function entity_crud_hook_test_block_presave() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_presave().
  */
 function entity_crud_hook_test_comment_presave() {
@@ -64,6 +71,13 @@ function entity_crud_hook_test_entity_insert(EntityInterface $entity) {
 }
 
 /**
+ * Implements hook_block_insert().
+ */
+function entity_crud_hook_test_block_insert() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_insert().
  */
 function entity_crud_hook_test_comment_insert() {
@@ -113,6 +127,13 @@ function entity_crud_hook_test_entity_load(array $entities, $type) {
 }
 
 /**
+ * Implements hook_block_load().
+ */
+function entity_crud_hook_test_block_load() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_load().
  */
 function entity_crud_hook_test_comment_load() {
@@ -162,6 +183,13 @@ function entity_crud_hook_test_entity_update(EntityInterface $entity) {
 }
 
 /**
+ * Implements hook_block_update().
+ */
+function entity_crud_hook_test_block_update() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_update().
  */
 function entity_crud_hook_test_comment_update() {
@@ -211,6 +239,13 @@ function entity_crud_hook_test_entity_predelete(EntityInterface $entity) {
 }
 
 /**
+ * Implements hook_block_predelete().
+ */
+function entity_crud_hook_test_block_predelete() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_predelete().
  */
 function entity_crud_hook_test_comment_predelete() {
@@ -260,6 +295,13 @@ function entity_crud_hook_test_entity_delete(EntityInterface $entity) {
 }
 
 /**
+ * Implements hook_block_delete().
+ */
+function entity_crud_hook_test_block_delete() {
+  $_SESSION['entity_crud_hook_test'][] = (__FUNCTION__ . ' called');
+}
+
+/**
  * Implements hook_comment_delete().
  */
 function entity_crud_hook_test_comment_delete() {
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
index 51bc8ee..996e15d 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserLoginBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'User login' block.
@@ -32,7 +33,7 @@ public function blockAccess() {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $form = drupal_get_form('user_login_form');
     unset($form['name']['#attributes']['autofocus']);
     unset($form['name']['#description']);
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
index 7f97df6..2ea4b89 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a "Who's new" block.
@@ -64,7 +65,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     // Retrieve a list of new users who have accessed the site successfully.
     $items = db_query_range('SELECT uid, name FROM {users} WHERE status <> 0 AND access <> 0 ORDER BY created DESC', 0, $this->configuration['whois_new_count'])->fetchAll();
     $build = array(
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
index 75f23f0..aee6ce1 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a "Who's online" block.
@@ -78,7 +79,7 @@ public function blockSubmit($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     // Count users active within the defined period.
     $interval = REQUEST_TIME - $this->configuration['seconds_online'];
 
diff --git a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
index 6d74ee4..7939f5c 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsBlock.php
@@ -11,6 +11,7 @@
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
 use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a generic Views block.
@@ -71,10 +72,10 @@ public function blockForm($form, &$form_state) {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $block) {
     $output = $this->view->executeDisplay($this->displayID);
-    // Set the subject to the title configured in the view.
-    $this->configuration['label'] = filter_xss_admin($this->view->getTitle());
+    // Set the label to the title configured in the view.
+    $block->set('label', filter_xss_admin($this->view->getTitle()));
     // Before returning the block output, convert it to a renderable array
     // with contextual links.
     views_add_block_contextual_links($output, $this->view, $this->displayID);
diff --git a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
index 2d51c25..40baebb 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Annotation\Plugin;
 use Drupal\Core\Annotation\Translation;
+use Drupal\block\Plugin\Core\Entity\Block;
 
 /**
  * Provides a 'Views Exposed Filter' block.
@@ -25,7 +26,7 @@ class ViewsExposedFilterBlock extends ViewsBlock {
   /**
    * Implements \Drupal\block\BlockBase::blockBuild().
    */
-  public function blockBuild() {
+  public function blockBuild(Block $entity) {
     $type = 'exp';
     $output = $this->view->display_handler->viewSpecialBlocks($type);
     // Before returning the block output, convert it to a renderable array with
diff --git a/core/profiles/standard/config/plugin.core.block.seven.help.yml b/core/profiles/standard/config/plugin.core.block.seven.help.yml
index 5b3ad82..bf2be94 100644
--- a/core/profiles/standard/config/plugin.core.block.seven.help.yml
+++ b/core/profiles/standard/config/plugin.core.block.seven.help.yml
@@ -1,4 +1,4 @@
-id: bartik.content
+id: seven.help
 plugin: system_help_block
 theme: seven
 status: '1'