Razor test: Gillette vs. Dollar Shave vs.Harry"s Oneof the darlings of theLos Angeles start-up scene is cashing in on a$1-billion payday a rise fueled by a disruptive business model and a series ofoffbeat viral ads.But this company doesnot traffic in virtual reality headsets, video games or disappearing messages. Its business, instead, focuses on one of mankinds oldest gadgets: razors.Dollar Shave Clubs sale to consumer...