Such a thing could provide significantly more useful information, too - I envisage a notification with "This site wants to use a cookie on your computer" at the top, "allow/deny, now/always" buttons and a "What are cookies?" link at the bottom, and a user-friendly breakdown of this particular case in between, things like:
• "only visible to this site" vs "visible to ad.doubleclick.net" etc - maybe including, say, the Organization Name from the cookie domain's SSL cert, at least in the case of cookies set to "Secure" (maybe only if the cert's EV)
• "until you close your browser" vs "for a week" etc - perhaps with a way for the user to force session-only if desired
• possibly some kind of warning about snooping risk if the cookie's not marked secure, or not HTTP-only & 3rd-party scripts are on the page, etc
• for the case of 3rd-party cookies, it'd be possible to list which other sites have used the same cookie in the past
And so forth. The most importantant point being that you could actually trust this information - your browser has no motivation to lie to you about it, but any random site might.
[0] eg, https://i.imgur.com/NcxWz8zh.jpg
The law allows storing session info, config options, etc without prompting. The browser couldn’t reliably test that.
Unless you’d also let login to sites be handled by the browser, akin to Mozilla’s Persona.
Damn, that’d actually be a much nicer web.
Or, to look at it another way... so what if the browser pops up notifications more often than the law requires? Might encourage people to make less use of cookies for functionality that doesn't really need them, which would be no tragedy. And if your site really can't do without them, you could pop up a message explaining the situation & politely asking to be unblocked.
I suppose there'd be a danger of alert fatigue... maybe some heuristic analysis of the cookies themselves would be in order, to at least tentatively classify them as "tracking" vs "other". Eg, Google Analytics & Piwik cookies could be identified pretty reliably.
But that's happening with the current solution as well (not to mention all those crappy sites with their modal popups that teach you to close anything opening asap anyway)