It is called Offline Music Importer. Free for 50 songs then paid after that. Not sure what the paid cost is. It did not let me choose the tracks to import just started going through my library.... I have not bought the full version yet. I let it run the 50 for free and the Car Media Player App seems to recognize them. It moved them to the Music Folder which was nice also.
https://play.google.com/store/apps/details?id=com.sapien.music.importer&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5zYXBpZW4ubXVzaWMuaW1wb3J0ZXIiXQ..