Letting you watch Hulu shows inside Disney’s flagship streaming service required a massive reengineering project—and reflects the company’s overarching vision for its future. Four years ago, The Walt Disney Co. seized control of its streaming destiny. Instead of continuing to provide content to the likes of Netflix, it rounded up its storied brands—Disney itself, Marvel, Pixar, Star Wars, National Geographic—and folded them into a family-friendly video platform called Disney Plus.