On a crisp January afternoon, the Shenzhen Bay Sports Centre, just a stone’s throw from Tencent Holdings’ headquarters, was packed with employees gathering for a party featuring celebrity cameos and prizes. But before the fun started, they witnessed a round of sober self-reflection from their low-profile leader. The New Year address by co-founder, chairman and CEO Pony Ma Huateng is an annual tradition for the social media and video gaming giant, offering its 115,000 employees rare insight into...