It is often useful to see what rectangles are being repainted. Adding a setting that allows toggling it.
Created attachment 127817 [details] Patch
Why does the client need to do this? Same reason the client does node highlights?
(In reply to comment #2) > Why does the client need to do this? Same reason the client does node highlights? I was going to expose the feature that was already there in Chrome first. I will try upstreaming it in case it sticks. Here is what it looks like in Chrome today: http://www.youtube.com/watch?v=Ea41RdQ1oFQ&t=1m30s
Hovering in the Timeline seems more interesting. That is a different API right?
Hovering in the Timeline is using data collected while instrumenting to highlight regions on the screen, so it is different. To your client concern, I'll rework this change to upstream Chrome's debug paint rects all in one change - should not be much work.
Created attachment 127939 [details] Patch
Committed r108330: <http://trac.webkit.org/changeset/108330>