drawArc(), addRoundedClipRect(), and addInnerRoundedClipRect() should be implemented in Cairo to match the mac side.
This is a followup bug for http://bugzilla.opendarwin.org/show_bug.cgi?id=6755
A lot of time has passed since this bug was filed. The functions may well have been implemented. Needs checking.
addInnerRoundedRectClip() seems to be there, others are still missing.
(In reply to comment #3) > addInnerRoundedRectClip() seems to be there, others are still missing. I looked a bit more carefully at these, and seems like drawArc was renamed to strokeArc and is actually implemented (though with some FIXME). Also, addRoundedRectClip is implemented in a platform-independent way in GraphicsContext.cpp. And (after realizing that since border-radius is still at draft stage) seems like -webkit-border-radius properties are working fine, so I suppose this bug can be closed :)
The patch at https://bugs.webkit.org/show_bug.cgi?id=20343 implemented border-radius to cairo and matches the mac side.