Customers for Doordash (DASH) are fans of the company's grocery delivery service. Likefolio's Megan Brantley calls it a major driver behind Doordash's accelerating growth. She shares data showing how the company keeps a tight race with competition like Maplebear's (CART) Instacart. Its partnerships with Lyft Inc. (LYFT) and The Trade Desk (TTD) didn't hurt, either.