diff --git a/core/lib/Drupal/Core/EventSubscriber/SmartCacheSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/SmartCacheSubscriber.php
index 51fde1b..963b201 100644
--- a/core/lib/Drupal/Core/EventSubscriber/SmartCacheSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/SmartCacheSubscriber.php
@@ -117,7 +117,8 @@ public function onRouteMatch(GetResponseEvent $event) {
   /**
    * {@inheritdoc}
    */
-  static function getSubscribedEvents() {
+  public static function getSubscribedEvents() {
+    $events = [];
     $events[KernelEvents::REQUEST][] = ['onRouteMatch', 27];
 
     return $events;
diff --git a/core/lib/Drupal/Core/PageCache/ResponsePolicy/NoAdminRoutes.php b/core/lib/Drupal/Core/PageCache/ResponsePolicy/NoAdminRoutes.php
index 97cec61..3c8dcdd 100644
--- a/core/lib/Drupal/Core/PageCache/ResponsePolicy/NoAdminRoutes.php
+++ b/core/lib/Drupal/Core/PageCache/ResponsePolicy/NoAdminRoutes.php
@@ -46,4 +46,3 @@ public function check(Response $response, Request $request) {
   }
 
 }
-
diff --git a/core/lib/Drupal/Core/Render/MainContent/SmartCacheHtmlRenderer.php b/core/lib/Drupal/Core/Render/MainContent/SmartCacheHtmlRenderer.php
index f9ab481..ccdca1d 100644
--- a/core/lib/Drupal/Core/Render/MainContent/SmartCacheHtmlRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/SmartCacheHtmlRenderer.php
@@ -16,11 +16,9 @@
 use Drupal\Core\PageCache\RequestPolicyInterface;
 use Drupal\Core\PageCache\ResponsePolicyInterface;
 use Drupal\Core\Render\Element;
-use Drupal\Core\Render\ElementInfoManagerInterface;
 use Drupal\Core\Render\RenderCacheInterface;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
-use Symfony\Component\DependencyInjection\ContainerAwareTrait;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Response;
@@ -121,7 +119,7 @@ protected function finish(array $html) {
     // already, then we can return early: no need to redo all the work.
     if (isset($html['#smartcache'])) {
       // Mark the response as a cache hit.
-      $html['#attached']['http_header'][] = ['X-Drupal-SmartCache',  'HIT'];
+      $html['#attached']['http_header'][] = ['X-Drupal-SmartCache', 'HIT'];
       return parent::finish($html);
     }
 
@@ -174,12 +172,12 @@ protected function finish(array $html) {
     //   the breadcrumbs block, which currently set max-age = 0, even though it
     //   is perfectly possible to cache them), to see the performance boost this
     //   will bring, uncomment this line.
-//    $html_cache_max_age = Cache::PERMANENT;
-
+    //   $html_cache_max_age = Cache::PERMANENT;
+    //
     // @todo Remove this. Work-around to support the deep-render-array-scanning-
-    //    dependent logic bartik_preprocess_html() has: it needs to know about
-    //    the presence or absence of certain regions. That is similar (but less
-    ///   bad) to the evil things one could do with hook_page_alter() in D7.
+    //   dependent logic bartik_preprocess_html() has: it needs to know about
+    //   the presence or absence of certain regions. That is similar (but less
+    //   bad) to the evil things one could do with hook_page_alter() in D7.
     foreach (Element::children($html['page']) as $page_region) {
       $cacheable_html['page'][$page_region] = ['#preprocess_functions_messing_with_cacheability' => TRUE];
     }
@@ -202,11 +200,11 @@ protected function finish(array $html) {
       $this->smartHtmlCache->set($cid, $cacheable_html, $expire, $html_cache_tags);
 
       // Now that the cacheable HTML is cached, mark the response as a cache miss.
-      $cacheable_html['#attached']['http_header'][] = ['X-Drupal-SmartCache',  'MISS'];
+      $cacheable_html['#attached']['http_header'][] = ['X-Drupal-SmartCache', 'MISS'];
     }
     else {
       // Now that the cacheable HTML is cached, mark the response as a cache miss.
-      $cacheable_html['#attached']['http_header'][] = ['X-Drupal-SmartCache',  'UNCACHEABLE'];
+      $cacheable_html['#attached']['http_header'][] = ['X-Drupal-SmartCache', 'UNCACHEABLE'];
     }
 
     return parent::finish($cacheable_html);
diff --git a/core/modules/system/src/Tests/Cache/SmartCacheIntegrationTest.php b/core/modules/system/src/Tests/Cache/SmartCacheIntegrationTest.php
index 5845969..8600e7d 100644
--- a/core/modules/system/src/Tests/Cache/SmartCacheIntegrationTest.php
+++ b/core/modules/system/src/Tests/Cache/SmartCacheIntegrationTest.php
@@ -45,7 +45,7 @@ protected function setUp() {
   /**
    * Tests that SmartCache works correctly, and verifies the edge cases.
    */
-  function testSmartCache() {
+  public function testSmartCache() {
     // Controllers returning response objects are ignored by SmartCache.
     $url = Url::fromUri('route:smart_cache_test.response');
     $this->drupalGet($url);