For automated accessibility testing, it would be great to be able to test how websites behave when a user sets a root font size that is different from the default 16px.

It requires a way to programmatically change the root font size of a headless Chrome, as a user could in the browser settings.

This would also be exposed in Pupeteer, for example. I already opened an issue on this project: https://github.com/GoogleChrome/puppeteer/issues/1157