Report replaced widgets in the popup UI

[ghostwords]

Sometimes widget replacement fails (#2331, #1542 (comment)), and sometimes it succeeds but our placeholder is unusable for some reason (Spotify, SoundCloud on Tumblr (#787), #2281).

When replacement fails for a blocked widget that provides/is required for desired functionality, it's not clear why a video is missing, a form that requires reCAPTCHA doesn't work, etc. as Privacy Badger doesn't show anything inside the page, nor anything specifically about video players or CAPTCHA providers in the popup.

When replacement succeeds but clicking our placeholder doesn't do anything, there is no obvious way to activate it in another way.

We should add UI to the popup to show the widgets that should have been replaced on the current page. This should help make it clear what Privacy Badger meant to replace. This will also allow users to activate each widget regardless of whether its replacement is present and usable.

[clasick]

Are there any UI guidelines for implementing this change?

[ablanathtanalba]

Are there any UI guidelines for implementing this change?

There isn't a UI guidelines doc we've been following for this change, though some work has taken place in #2799 which follows a few other recent branches of work that have gone towards a similar goal of adding more expressive content to the extension popup

[ghostwords]

I had some thoughts regarding the UI in #2758 (comment)

[ablanathtanalba]

@clasick if you'd like to contribute or collaborate on #2799, let's talk! Feel free to leave any questions or comments on #2799, or if you'd like to join one of our upcoming biweekly developer meetings, we can chat about it there. Meeting details can be found here

[ghostwords]

Firefox is adding click-to-activate widgets ("Smartblock embeds"), controlled through the Tracking Protections panel: