core/modules/outside_in/outside_in.module                         | 8 +++++++-
 .../src/Access/BlockPluginHasOffCanvasFormAccessCheck.php         | 7 ++++++-
 .../Unit/Access/BlockPluginHasOffCanvasFormAccessCheckTest.php    | 4 ++--
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/core/modules/outside_in/outside_in.module b/core/modules/outside_in/outside_in.module
index 92bcd94..dec2abb 100644
--- a/core/modules/outside_in/outside_in.module
+++ b/core/modules/outside_in/outside_in.module
@@ -109,7 +109,13 @@ function outside_in_preprocess_block(&$variables) {
   // guarantee a smooth experience.
   // This is an implementation detail that may change in the future.
   // @see \Drupal\outside_in\Access\BlockPluginHasOffCanvasFormAccessCheck
-  if (\Drupal::service('plugin.manager.block')->createInstance($variables['plugin_id'])->hasFormClass('off_canvas')) {
+  /** @var \Drupal\outside_in\Access\BlockPluginHasOffCanvasFormAccessCheck $access_checker */
+  $access_checker = \Drupal::service('access_check.outside_in.block.off_canvas_form');
+  /** @var \Drupal\Core\Block\BlockManagerInterface $block_plugin_manager */
+  $block_plugin_manager = \Drupal::service('plugin.manager.block');
+  /** @var \Drupal\Core\Block\BlockPluginInterface $block_plugin */
+  $block_plugin = $block_plugin_manager->createInstance($variables['plugin_id']);
+  if ($access_checker->accessBlockPlugin($block_plugin)) {
     // Add class and attributes to all blocks to allow Javascript to target.
     $variables['attributes']['class'][] = 'outside-in-editable';
     $variables['attributes']['data-drupal-outsidein'] = 'editable';
diff --git a/core/modules/outside_in/src/Access/BlockPluginHasOffCanvasFormAccessCheck.php b/core/modules/outside_in/src/Access/BlockPluginHasOffCanvasFormAccessCheck.php
index 83ebdef..6966943 100644
--- a/core/modules/outside_in/src/Access/BlockPluginHasOffCanvasFormAccessCheck.php
+++ b/core/modules/outside_in/src/Access/BlockPluginHasOffCanvasFormAccessCheck.php
@@ -9,6 +9,8 @@
 
 /**
  * Determines whether the requested block has an 'off_canvas' form.
+ *
+ * @internal
  */
 class BlockPluginHasOffCanvasFormAccessCheck implements AccessInterface {
 
@@ -21,7 +23,7 @@ class BlockPluginHasOffCanvasFormAccessCheck implements AccessInterface {
    * @return \Drupal\Core\Access\AccessResultInterface
    *   The access result.
    */
-  public function accessBlock(BlockInterface $block) {
+  public function access(BlockInterface $block) {
     /** @var \Drupal\Core\Block\BlockPluginInterface $block_plugin */
     $block_plugin = $block->getPlugin();
     return $this->accessBlockPlugin($block_plugin);
@@ -35,6 +37,9 @@ public function accessBlock(BlockInterface $block) {
    *
    * @return \Drupal\Core\Access\AccessResultInterface
    *   The access result.
+   *
+   * @see outside_in_preprocess_block()
+   * @todo Remove when outside_in_preprocess_block() is removed.
    */
   public function accessBlockPlugin(BlockPluginInterface $block_plugin) {
     return AccessResult::allowedIf($block_plugin->hasFormClass('off_canvas'));
diff --git a/core/modules/outside_in/tests/src/Unit/Access/BlockPluginHasOffCanvasFormAccessCheckTest.php b/core/modules/outside_in/tests/src/Unit/Access/BlockPluginHasOffCanvasFormAccessCheckTest.php
index 104e45d..6d5366b 100644
--- a/core/modules/outside_in/tests/src/Unit/Access/BlockPluginHasOffCanvasFormAccessCheckTest.php
+++ b/core/modules/outside_in/tests/src/Unit/Access/BlockPluginHasOffCanvasFormAccessCheckTest.php
@@ -17,7 +17,7 @@
 class BlockPluginHasOffCanvasFormAccessCheckTest extends UnitTestCase {
 
   /**
-   * @covers ::accessBlock
+   * @covers ::access
    * @covers ::accessBlockPlugin
    * @dataProvider providerTestAccess
    */
@@ -27,7 +27,7 @@ public function testAccess(array $plugin_definition, AccessResultInterface $expe
     $block->getPlugin()->willReturn($block_plugin);
 
     $access_check = new BlockPluginHasOffCanvasFormAccessCheck();
-    $this->assertEquals($expected_access_result, $access_check->accessBlock($block->reveal()));
+    $this->assertEquals($expected_access_result, $access_check->access($block->reveal()));
     $this->assertEquals($expected_access_result, $access_check->accessBlockPlugin($block_plugin));
   }