Issue #2643888 by Devin Carlson: Remove dependency on Composer Manage…

…r in favour of implementing hook_requirements().

url_embed.info.yml

@@ -4,7 +4,6 @@ description: 'Allows URLs to be embedded using a text editor.'
 core: 8.x
 package: Filters
 dependencies:
-  - composer_manager
   - editor
   - embed
   - filter

url_embed.install

@@ -8,6 +8,26 @@
 use Drupal\embed\Entity\EmbedButton;
 use Drupal\Core\Utility\UpdateException;
 
+/**
+ * Implements hook_requirements().
+ *
+ * Checks that the necessary libraries have been installed.
+ */
+function url_embed_requirements($phase) {
+  $requirements = [];
+
+  if ($phase === 'install') {
+    if (!class_exists('\Embed\Embed')) {
+      $requirements['url_embed_library'] = [
+        'description' => t("URL Embed requires the Embed/Embed library."),
+        'severity' => REQUIREMENT_ERROR,
+      ];
+    }
+  }
+
+  return $requirements;
+}
+
 /**
  * Convert URL embed buttons to embed buttons.
  *