The plum in question, Ume, is a different species than is commonly found in supermarkets here in the States. It seems an odd thing to pair the sweet and sourness of the plum with cream cheese in a tortilla chip.
Rather than falling under the Doritos brand (Tostitos aren't offered in Japan), the chips are simply labeled as "tortilla chips."
Frito-Lay's Plum & Cheese Tortilla Chips are set to come out in 75g bags starting January 26, 2015 through April 20, 2015.