1844443 - Do not register Windows native notification callbacks in Firefox when running in background task mode

Status: NEW

(Toolkit :: Application Update, enhancement, P3)

Description

[Nick Alexander :nalexander [he/him]]

Bug 1844335 notes a subtle interaction between about:newtab#asrouter and the toast notification message type where clicking toast notifications while Firefox is still running does not produce the desired effect. At this time, that's expected -- but it's misleading.

We could avoid this by having the WindowsAlertsService not register Firefox-side callbacks when we're in background task mode and, potentially, when invoked during testing. This would force every toast notification to follow the relaunch flow, avoiding some confusion about why things aren't happening. It would introduce some confusion and differences because the relaunch flow happens earlier in startup, potentially with a different window configuration and with different race conditions, etc.

Overall, I think this is worth pursuing.