Violent protests have broken out in Zhengzhou, China, following contract disputes at the world’s biggest Apple iPhone factory, according to videos posted on social media and verified by NBC News. The footage was taken near the Foxconn factory, in the streets of the Zhengzhou Airport Economy Zone, where large groups of people blocked roads during their protest. The videos circulated on Chinese social media, although several were taken down by censors. A worker disinfects the Foxconn factory in Zhengzhou, China on Nov. 6. VCG via Getty Images file The images show thousands of people in masks protesting against police in...