There's a big upheaval afoot at Google -- Android lead Andy Rubin is stepping down from his position to "start a new chapter" at the company. Sundar Pichai, who currently oversees the Apps and Chrome projects, will take over the top spot in mobile. Neither the company nor Rubin have explained the reasoning for the management change so far, although it's safe to say that Rubin is going out on a high note when most smartphones sold today use the OS he helped create.Filed under: