Remove Online Accounts support
As part of the ongoing work to revitalise GNOME Online Accounts, it no longer uses an embedded webview for account authentication and instead uses the system web browser (gnome-online-accounts!139 (merged)). This is both for desirable usability reasons – better to use your normal trusted web browser that may even already be logged into your online account than a random webview – and also because the providers of the online accounts in question very strongly prefer not to allow people to log in via an embedded webview for security/anti-phishing reasons.
However, by design, it is not possible to open the system web browser from the Initial Setup session. At a technical level, this is achieved by setting the handler for http(s) URLs to a dummy app that just runs /bin/true. At a conceptual level, this is because the Initial Setup session is meant to be a special-purpose kiosk, not an environment for general-purpose web browsing etc.
It may be technically possible to wire up a WebKitGTK-based browser window in Initial Setup (going against the wishes of service providers); or to run the system browser (either in a kiosk mode, or in a normal mode and accept that it breaks the kiosk model); but instead we propose to simply remove the Online Accounts integration from Initial Setup.
The downsides are that this means we will no longer be able to fetch the user's real name from their online accounts(s), and in theory default to their avatar from an online account (though this has been broken for a while, #98 (closed)).
The upside is that it's one less step standing between the user and a fully-featured session on their new computer; no confusing flows with web browser popovers; less code to maintain (we just need one interface for configuring online accounts, in Settings); and we have a possibly-uninformed belief that this functionality is not that widely used and will not be missed too much.
If there is a strong desire to guide new users to set up online accounts, this could be added to GNOME Tour, as a call to action that launches the Online Accounts section of Settings when clicked.