In July, Mahe a star engineer at Apple was named the tech giant’s first-ever vice president and managing director of Greater China. The region that includes the world’s second largest economy is vital to Apple,it generated 18% of the company’s revenue in the most recent quarter. But Mahe took over the region as sales there slipped for the sixth consecutive quarter, raising the stakes of the latest iPhone release. The new role, based in Shanghai, also constituted a homecoming for Mahe. The Mandarin speaker was born in China but had lived in Canada and the United States since age 16.