I was confused when looking at the map, how come China is Chrome when google is not even allowed in China. Then I remember all those ad-riddled Chinese browsers that are based on Chrome.
They're likely based on Chromium, which is what Google Chrome is based on. Chromium is open-source. Chrome is not.
Not that China cares about US copyright. But it's still easier to just use open-source code rather than creating a browser from scratch or cracking open the code of a proprietary browser.