code: protected function registerAssetFiles($name)
      {
          if (!isset($this->assetBundles[$name])) {
              return;
          }
          $bundle = $this->assetBundles[$name];
          if ($bundle) {
              foreach ($bundle->depends as $dep) {
                  $this->registerAssetFiles($dep);
              }
              $bundle->registerAssetFiles($this);
          }
          unset($this->assetBundles[$name]);
      }
docs: Registers all files provided by an asset bundle including depending bundles files.
  Removes a bundle from [[assetBundles]] once files are registered.
  @param string $name name of the bundle to register