Mail.Ru is one of the most popular email service provider in Russia.
The documentation for Mail.Ru's OAuth2 endpoints is at
https://o2.mail.ru/docs/
Change-Id: I605979b85cff2b00c7b65bbd3306d3fa66faa56d
Reviewed-on: https://go-review.googlesource.com/84415
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Vladimir Varankin