Chrome, FF and WebKitGTK manage to enable subpixel positioning to draw a test page like in the URL field.
The font rendering on WebKitEFL looks rather ugly in comparison. No subpixel positioning, only grayscale antialiasing.
We should try to enable that before doing the subpixel rebaselining.
Can you attach screenshot?
How do you intent to enable this?
Cairo does not support subpixel positioning at this point, I filed this bug a bit prematurely.