By Norihiko Shirouzu BEIJING (Reuters) – SAIC Mobility, a unit of Chinese automaker SAIC Motor, and self-driving startup Momenta have begun offering autonomous robot taxi test trips to the public in a district of Shanghai, Momenta said on Wednesday. The companies are operating 20 taxi robots to assess their viability for commercial use in a trial that will expand to a second Chinese city next year, Momenta said. SAIC was not immediately available for comment. Beijing-based Momenta said companies are exploring the application of so-called “Level 4” fully autonomous driving technology to urban travel. Pilots can call a robot taxi...