WebKit with Cairo
Adobe, to be able to make their proprietary platform for application developement, using Flash, did use the Open Source WebKit (that same HTML engin that Apple use for Safari, that is based on KHTML). The paradox is that to have WebKit work on Windows, they used Cairo as a backend. The good news is that Cairo is likely to get better and that WebKit using Cairo is likely to help greatly a Gtk based version.
Changes are available for people to use.
 in that case it is more about the silo than the code