Fixes after code review

Author: andrewbess

app/code/Magento/Widget/Controller/Adminhtml/Widget/Index.php

@@ -1,6 +1,5 @@
 <?php
 /**
- *
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
@@ -13,11 +12,9 @@ class Index extends \Magento\Backend\App\Action implements HttpPostActionInterfa
     /**
      * Authorization level of a basic admin session
      */
-    const ADMIN_RESOURCE = 'Magento_Widget::widget_instance';
+    public const ADMIN_RESOURCE = 'Magento_Widget::widget_instance';
 
     /**
-     * Core registry
-     *
      * @var \Magento\Framework\Registry
      */
     protected $_coreRegistry;
@@ -50,11 +47,11 @@ public function __construct(
     public function execute()
     {
         // save extra params for widgets insertion form
-        $skipped = $this->getRequest()->getParam('skip_widgets');
+        $skipped = $this->getRequest()->getParam('skip_widgets', '');
         $skipped = $this->_widgetConfig->decodeWidgetsFromQuery($skipped);
-
         $this->_coreRegistry->register('skip_widgets', $skipped);
 
+        // phpcs:ignore Magento2.Legacy.ObsoleteResponse
         $this->_view->loadLayout('empty')->renderLayout();
     }
 }

lib/internal/Magento/Framework/Url/Decoder.php

@@ -24,14 +24,14 @@ public function __construct(
     }
 
     /**
-     * Base64 decode for URL
+     * base64_decode() for URLs decoding
      *
      * @param    string $url
      * @return   string
      */
     public function decode($url)
     {
-        $url = $url !== null ? base64_decode(strtr($url, '-_,', '+/=')) : '';
+        $url = base64_decode(strtr($url, '-_,', '+/='));
         return $this->urlBuilder->sessionUrlVar($url);
     }
 }