That's the internal API used by the hangout_services extension. It's the extension itself that is undocumented.
A user might reasonably expect that web pages do not have access to the system.cpu API by default. And that's mostly true, but thanks to the pre-installed but hidden hangout_services extension, google.com does have access to this API. That's at least a little dubious.
A user might reasonably expect that web pages do not have access to the system.cpu API by default. And that's mostly true, but thanks to the pre-installed but hidden hangout_services extension, google.com does have access to this API. That's at least a little dubious.