Grappling with a shrinking share of the smartphone market, Research in Motion has pacted with London-based 7digital to supply music downloads for its BlackBerry 10, to be released in the first quarter of 2013.As the official download provider for the BlackBerry 10, 7digital, a supplier of low-priced album downloads, will deliver more than 22 million licensed tracks to RIM’s BlackBerry App World. Offerings will encompass new and catalog releases, regional music and indie artists. The music service will also integrate 7digital’s open music platform with BlackBerry platform abilities, such as social integration and recommendation engines. Announcement of BlackBerry’s beefed-up music content comes as the once-dominant smartphone has been eclipsed by the iPhone, Android and other new-look devices. In just three years, RIM’s share of the smartphone market has slid from 50% to less than 5% in the U.S. In September, the Canadian company posted a quarterly loss of $235 million, vs. earnings of $329 million in the same quarter last year. RIM’s co-CEOs resigned in January. Development of the BlackBerry 10 has lagged, and some observers have noted its tardy introduction early next year will cut out the lucrative Christmas market for new gadgets.