Override Gin local actions block to render links in a dropbutton.

modules/core/ui/theme/farm_ui_theme.install

@@ -60,4 +60,24 @@ function farm_ui_theme_install() {
     ],
   ];
   Block::create($values)->save();
+
+  // Modify the block.block.gin_local_actions config to use our class.
+  $local_actions_block = \Drupal::configFactory()->getEditable('block.block.gin_local_actions');
+  $local_actions_block->set('plugin', 'farm_local_actions_block');
+  $local_actions_block->set('settings.id', 'farm_local_actions_block');
+  $local_actions_block->set('settings.provider', 'farm_ui_theme');
+  $local_actions_block->save();
+}
+
+/**
+ * Implements hook_uninstall().
+ */
+function farm_ui_theme_uninstall() {
+
+  // Revert changes to block.block.gin_local_actions config.
+  $local_actions_block = \Drupal::configFactory()->getEditable('block.block.gin_local_actions');
+  $local_actions_block->set('plugin', 'local_actions_block');
+  $local_actions_block->set('settings.id', 'local_actions_block');
+  $local_actions_block->set('settings.provider', 'core');
+  $local_actions_block->save();
 }

modules/core/ui/theme/src/Plugin/Block/FarmLocalActionsBlock.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Drupal\farm_ui_theme\Plugin\Block;
+
+use Drupal\Core\Menu\Plugin\Block\LocalActionsBlock;
+
+/**
+ * Provides a block to display the local actions.
+ *
+ * @Block(
+ *   id = "farm_local_actions_block",
+ *   admin_label = @Translation("Primary farm admin actions")
+ * )
+ */
+class FarmLocalActionsBlock extends LocalActionsBlock {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build() {
+
+    // Render local actions as a dropbutton.
+    $local_actions = parent::build();
+    $links = [];
+    foreach ($local_actions as $local_action) {
+      if (!empty($local_action['#link']) && $local_action['#access']->isAllowed()) {
+        $links[] = $local_action['#link'];
+      }
+    }
+    return [
+      '#type' => 'dropbutton',
+      '#dropbutton_type' => 'standard',
+      '#links' => $links,
+      '#cache' => $local_actions['#cache'],
+    ];
+  }
+
+}