Kindly inform Web developers that they should use requestAnimationFrame instead with this message:
"'webkitRequestAnimationFrame' is vendor-specific. Please use the standard 'requestAnimationFrame' instead."
Pages that fails to use the standard requestAnimationFrame when available make it impossible for webkitRequestAnimationFrame to ever be removed. More importantly, it can contribute to browser engine lock-in. (Not must, because it's possible the script would fall back to the standard API.)