An actor of laid-back charm, gravelly voice and rugged looks, Dermot Mulroney embodied the toughness and vulnerability of onscreen male maturation. After spending the 1990s crafting intimate roles in well-regarded indie films, Mulroney was thrust into the mainstream spotlight – first, as Holly Hunter’s doomed police partner in the serial killer flick “Copycat” (1995), and more importantly, as romantic leading man to Julia Roberts in the star-making blockbuster, “My Best Friend’s Wedding” (1997). His role in the latter romantic comedy was so highly identifiable with Mulroney, that he spent the