src/Plugin/FileSystemPluginLocator.php
public function getInstalledPlugins($path) {
        $searchPluginDirectories = $this->searchPluginDirectories($path);
        $validPluginDirectories  = array();
        $factoryPluginClasses    = array();
        foreach ($searchPluginDirectories as $pluginDirectory) {
            if (is_file($pluginDirectory. '/enable.php')) {
                $validPluginClass = $this->searchPluginFactoryClass($pluginDirectory);
                if ($validPluginClass) {
                    $validPluginDirectories[] = $pluginDirectory;
                    $factoryPluginClasses[] = $validPluginClass;
                }
            }
        }
        return array('pluginClasses'    => $factoryPluginClasses,
                     'pluginDirectories'=> $validPluginDirectories,
                     'pluginEnabled'    => true
                     );
    }
public function getInstalledPlugins($path) {
        $searchPluginDirectories = $this->searchPluginDirectories($path);
        $validPluginDirectories  = array();
        $factoryPluginClasses    = array();
        foreach ($searchPluginDirectories as $pluginDirectory) {
            if (is_file($pluginDirectory. '/enable.php')) {
                $validPluginClass = $this->searchPluginFactoryClass($pluginDirectory);
                if ($validPluginClass) {
                    $validPluginDirectories[] = $pluginDirectory;
                    $factoryPluginClasses[] = $validPluginClass;
                }
            }
        }
        return array('pluginClasses'    => $factoryPluginClasses,
                     'pluginDirectories'=> $validPluginDirectories,
                     'pluginEnabled'    => true
                     );
    }
Return all the plugin installed classes found in the concrete path.

@param string $path
@return array('pluginClasses'=>$factoryPluginClasses,'pluginDirectories'=>$validPluginDirectories)