Tick the checkbox for Open Google OAuth Screen in Browser in App Options
Tick the checkbox for Support App Protocol and enter a protocol
App Options in app.todesktop.com
Redirect instead of showing prompt
This depends on how you've implemented sign in with google but the key thing is that you need to sign in with a redirect not with a prompt.
For ToDesktop's App we use Firebase. Firebase has a function firebase.auth().signInWithRedirect(googleProvider) which seems like it would do the job however the redirect doesn't include the id_token so instead we have to do the authentication manually
Here we use window.todesktop to check if we're in the Desktop app. If so, we load auth2 into GAPI, initialize it with our project's client id, and then get an auth instance and start the redirect sign in.
You can find your project's Google Client ID in your Project's Developers Console Credentials page.