diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php b/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
index dd6a5a5..7a10c8a 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
@@ -68,7 +68,7 @@ function setUp() {
     );
 
     $block_storage = $this->container->get('entity.manager')->getStorageController('block');
-    $blocks = $block_storage->loadByProperties(array('theme' => variable_get('theme_default', 'stark')));
+    $blocks = $block_storage->loadByProperties(array('theme' => \Drupal::config('system.theme')->get('default')));
     foreach ($blocks as $block) {
       $block->delete();
     }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php b/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
index 962213a..f32a14c 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
@@ -85,33 +85,6 @@ public function blockSubmit($form, &$form_state) {
   }
 
   /**
-   * Generates a views block instance ID.
-   *
-   * @param \Drupal\Core\Config\Entity\Query\Query $entity_query
-   *   The entity query for a block.
-   *
-   * @return string
-   *   The new block instance ID.
-   */
-   public function generateBlockInstanceID(Query $entity_query) {
-     $original_id = 'views_block__' . $this->view->storage->id() . '_' . $this->view->current_display;
-
-     // Get an array of block IDs.
-     $block_ids = $entity_query->execute();
-
-     // Iterate through potential IDs until we get a new one. E.g.
-     // 'views_block__MYVIEW_PAGE_1_2'
-     $count = 1;
-     $id = $original_id;
-     while (in_array($id, $block_ids)) {
-       $id = $original_id . '_' . ++$count;
-     }
-
-     return $id;
-   }
-
-
-  /**
    * {@inheritdoc}
    */
   public function getMachineNameSuggestion() {
diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
index c759da0..33e0b72 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
@@ -120,11 +120,11 @@ public function testExposedBlock() {
     $this->drupalGet('test_exposed_block');
 
     // Test there is an exposed form in a block.
-    $xpath = $this->buildXPathQuery('//div[@id=:id]/div/form/@id', array(':id' => drupal_html_class('block-' . $block->id())));
+    $xpath = $this->buildXPathQuery('//div[@id=:id]/div/form/@id', array(':id' => drupal_html_id('block-' . $block->id())));
     $this->assertFieldByXpath($xpath, $this->getExpectedExposedFormId($view), 'Expected form found in views block.');
 
     // Test there is not an exposed form in the view page content area.
-    $xpath = $this->buildXPathQuery('//div[@class="view-content"]/form/@id', array(':id' => drupal_html_class('block-' . $block->id())));
+    $xpath = $this->buildXPathQuery('//div[@class="view-content"]/form/@id', array(':id' => drupal_html_id('block-' . $block->id())));
     $this->assertNoFieldByXpath($xpath, $this->getExpectedExposedFormId($view), 'No exposed form found in views content region.');
 
     // Test there is only one views exposed form on the page.