With “How to Train Your Dragon,” DreamWorks has embraced maturity over fart jokes and emerged a force to be reckoned with come Oscar time.Adapted loosely from the children’s book series by Cressida Cowell, “How to Train Your Dragon” follows the travails of village misfit Hiccup, who eventually prevails in changing his compatriots’ perceptions of their fire-breathing foes by befriending the most fearsome of their winged assailants — a sleek black Night Fury, which, upon closer inspection, shares traits more akin to cats, dogs and other domesticated animals than the terrifying menace suggested by local dragon lore. It’s a simple enough idea, but the rich script gives the actors voicing Hiccup and the Vikings meaty characters to work with, amounting to a sincere parable about peaceful coexistence, while still thrilling kids. DreamWorks’ nabbed an adapted screenplay nom in 2001 with “Shrek,” giving the studio hope in that category for this, its second book-based toon. And with a field of 10 picture noms, “Dragon” has a shot of flying in and taking a spot, much like “Up” did in 2009. The question remains whether the Academy will deign to honor two animated films in its top race when the precedent clearly belongs to Pixar.