In WebKit2 code including config.h is not needed but check-webkit-style complains about it's absence: Found header this file implements before WebCore config.h. Should be: config.h, primary header, blank line, and then alphabetically sorted. [build/include_order] [4]
Additionally we should mention in "WebKit Coding Style Guidelines" that including config.h is unnecessary.
Sounds like this was fixed in 48638. *** This bug has been marked as a duplicate of bug 48638 ***