This introduces a new timeline event category named "Painting" and assigned changes paint and compositing events to this category. The rationale behind this is that while style recalculation and rendering times are defined by DOM and CSS structure, comopsiting and painting is mostly defined by the visual appearance of the elements.
Created attachment 142709 [details] Patch
Created attachment 142710 [details] screenshot
Could we render overview for paint and layout using single row instead?
Comment on attachment 142709 [details] Patch Clearing r? from the patch since we agreed to render pain on the same overview bar.
Created attachment 143841 [details] Patch
Committed r118527: <http://trac.webkit.org/changeset/118527>