Yes, that was the idea. The problem is where to add it, to the tab? at the left after the favicon or at the right before the close button? There isn't many space in tabs (when you have a lot open which is very common), but there's plenty of free space in the toolbar/headerbar.

The point is to put it on the tab so that you can tell which tab(s) is playing audio. I was thinking we would just replace the favicon with the play icon in this case.

Created attachment 295165 [details] [review]
Show a speaker icon in tabs that are playing audio

Created attachment 295166 [details]
Screenshot

I'd replace the favicon instead, as it's more relevant that it's playing something than which website it is. It also avoids wasting more space in width-constrained usage.

(In reply to comment #5)
> I'd replace the favicon instead, as it's more relevant that it's playing
> something than which website it is. It also avoids wasting more space in
> width-constrained usage.

I thought about it, but tried this way to see how it looked, because it looks nice keeping the favicon so I left it this way. If it becomes a problem of space eventually we could try replacing the favicon.

I've pushed the patch as it is for now, feel free to update it to replace the favicon if it's really a problem for tab space.