For context, the feature request comes from trying to improve the experience for Android OAuth 2.0 flow via Custom Chrome tabs (https://github.com/openid/AppAuth-Android) within the Google Home Android app. Using Custom Chrome tabs as means to host the authentication flow is the Google Identity team's recommended approach for OAuth 2.0 integration.

Per the Google Identity team's recommendation, to avoid having a hanging Custom Chrome tab process upon completing the authentication flow (triggering an intent back to the client app) we've added the Intent.FLAG_ACTIVITY_NO_HISTORY flag to the custom tab intent.

However as a result, this is disruptive to 2-step factor authentication flows such as for users attempting to sign into Spotify with their Facebook. When users use this option to authenticate, they must login to Facebook first within the chrome tab. However users with 2-step verification for this flow must retrieve a security code from the Facebook app. However upon leaving the custom Chrome Chrome tab, it automatically closes due to the Intent.FLAG_ACTIVITY_NO_HISTORY. This leaves users who've created Spotify accounts via Facebook with 2 step verification unable to authenticate. See b/37588763 for more information.

Ideally we'd like to configure our Custom Chrome tab session to close when an intent is triggered within the Custom Chrome tab. This way we can avoid using the Intent.FLAG_ACTIVITY_NO_HISTORY flag which addresses the dangling Custom Chrome tab processes after OAuth flows and instead will close the tab when an intent is triggered to return back to the calling app.