Google sign-in in website detecting user accounts and display in iframe/popup

Well I'm trying to enable my users to login with their gmail accounts like I saw in some sites on the top right of the browser windows as I show in the image. The only thing I could get searching was use the Google Sign-in API but that let me create a button which open a popup with my accounts but I want to show it when the user get to the site without a new window, maybe a iframe or popup I dont know. Do anyone knows if what the image show can be done with Google Sign-In or it's maybe with another API or something?

Thanks!