You might as well say that Trolltech (QT makers) are doing it, because Nokia just acquired Trolltech (and QT).
Firefox is built on the quite nice Cairo graphics layer (At least Fx3). The QT port just adds a QT wrapper for the Cairo renderer implementation.
I know, But Trolltech are soon fully integrated with Nokia Services & Software, and its quite long time ago since they acquired Trolltech in January/February

. And when its not a real Subsidiary like Nokia Siemens Networks, Navteq, Vertu its Nokia who has ported it.
GTK 2 are built around Cairo
