Apple has filed a lawsuit against a former employee, alleging that he stole trade secrets related to the Apple Watch and shared them with his new employer, Chinese smartphone maker Oppo, which was aware of these activities. The complaint, filed on Thursday in federal court in San Jose, California, claimed that Shi Chen, a former sensor system architect for the Apple Watch team, obtained confidential information from the iPhone maker before joining Oppo’s Silicon Valley-based US research arm,...