Constructs a AggregatorPluginManager object.
string $type: The plugin type, for example fetcher.
\Traversable $namespaces: An object that implements \Traversable which contains the root paths keyed by the corresponding namespace to look for plugin implementations,
public function __construct($type, \Traversable $namespaces) {
$type_annotations = array(
'fetcher' => 'Drupal\\aggregator\\Annotation\\AggregatorFetcher',
'parser' => 'Drupal\\aggregator\\Annotation\\AggregatorParser',
'processor' => 'Drupal\\aggregator\\Annotation\\AggregatorProcessor',
);
$annotation_namespaces = array(
'Drupal\\aggregator\\Annotation' => DRUPAL_ROOT . '/core/modules/aggregator/lib',
);
$this->discovery = new AnnotatedClassDiscovery("aggregator/{$type}", $namespaces, $annotation_namespaces, $type_annotations[$type]);
$this->discovery = new CacheDecorator($this->discovery, "aggregator_{$type}:" . language(Language::TYPE_INTERFACE)->langcode);
$this->factory = new DefaultFactory($this->discovery);
}