Chinese handset vendor OnePlus is retreating from the US and European markets amid deepening woes from a memory crisis hammering the global smartphone industry. “After thorough evaluation, OnePlus has decided to conclude product roll-outs in Europe and North America,” the brand operated under Chinese smartphone maker Oppo said on its website on Thursday. OnePlus said it would continue to support existing devices with software updates, security patches and after-sales service, without providing a...