In “The Desperate Hour” (formerly titled “Lakewood”), Naomi Watts plays Amy Carr, who starts out in the late afternoon jogging through an upscale wooded suburb, mourning her husband’s death in a car crash the year before. The film tells the story of a woman and her partner, her significant other, the second self she can’t live without. The husband, named Peter, was friendly and bearded; we see him in a photo and hear him on a voicemail message, and he sounds like an ideal middle-class protector and mensch. She’s distraught without him.But that’s not the partner I’m talking about. “The Desperate Hour,” you see, is the tale of a woman and her trusty cell phone. In a way it’s their love story.In the last 25 years or so, there has been a species of movie — not quite a genre, more of an occasional blip — in which a brand of digital technology that is novel at the time gets a workout, both as structural device and as an exploration of how that technology is changing the world’s spirit. There...