differences between ff and chrome

[ ] manifest v3
[ ] no menus permission (use contextMenus)
[ ] no browser.menus either
[ ] no tabs context type in contextMenus.create
[ ] no background/scripts in manifest; need background/service_worker
- this actually screwed me for an hour (having put service_workers instead); chrome shrieks about the syntax of manifest keys at the root level but apparently ignores anything under that
  - it’s actually interesting because it shrieks about stuff that’s needed for firefox but doesn’t affect chrome, so you couldn’t actually have the same manifest file for both
[ ] no browser.contextMenus.onShown or onHidden event handlers
- this means that event handlers will have to get called whenever a tab (or window) is opened or closed and any time a new url is loaded
- tab onCreated, onRemoved, onReplaced?
- webNavigation onCommitted (probably)
- also probably should do runtime.onInstalled as well to do the initial cache generation
- actually may be able to get away with tab.onUpdated for refreshing the cacheab
- will need a separate tab.onActivated handler to regenerate the actual context menu though
[ ] chrome has tab groups which could be a question mark around behaviour

apparently we need a new design

okay so the big problem is: firefox can compute the context menus in one shot when they are opened (via menus.onShown), but chrome cannot, because it doesn’t have an onShown event.
instead, we will need a mapping of domains to tab IDs
- or more accurately, scheme -> domain/authority/whatever
- we also need the full stack of domain labels, eg foobar.dildo.biz, dildo.biz, biz
- of course we fold http/https together but other URI schemes should get their own root
- we can just scan these for the totals
- we may want to cache the window ids too but that could be getting ahead of ourselves and may not even be necessary
this mapping will have to be recomputed every time a tab is updated (which will fire implicitly after it is created) or removed
the context menu itself will have to be refreshed when the current tab is activated
this is not actually a bad change and might make the firefox version a little snappier because the expensive part is currently being computed whenever you open the context menu, when it actually can get away with only being computed whenever a tab changes URL (or is killed).
- it is, however, a pain in the ass, because it was working fine in firefox and now i have to rip up the fuckin floorboards to make it work in chrome