Starbucks Corp (SBUX.O) and Danone SA (DANO.PA) on Tuesday will begin selling a smoothie line at more than 4,300 U.S. Starbucks shops as part of a Greek yogurt partnership that will also include yogurt parfaits and ready-to-eat yogurt to be sold by grocers. The rollout comes as Starbucks seeks to double food sales and as Danone’s popular Dannon yogurt brand wrestles with Chobani in the popular Greek yogurt category. The coffee chain, which has about 12,000 U.S.