Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Use case

It's not super clear by the instructions, however the API seems to suggest that the CodeClient is able to do incremental authorization through the include_granted_scopes configuration value.

The current implementation of google_sign_in_web exposes a CodeClient that only supports setting scopes when it's created, but not again when it's used.

Proposal

Modify the API that the web plugin exposes of the CodeClient so additional scopes can be requested as needed. This might entail:

• Add a List<String> scopes parameter to the requestServerAuthCode
• Re-create the CodeClient as needed to support multiple requests
• Pass the include_granted_scopes parameter when creating the client