The Qt port does not correctly choose the fonts specified in HTML/CSS.
This is a placeholder bug that we classify as showstopper for Qt 4.6.
In FontCache::getCachedFontPlatformData() we ignore the family argument which contains the resolved real font family from the web settings, and instead we pass on the generic font family to Qt.
See also http://www.w3.org/TR/CSS2/fonts.html#generic-font-families
Quick fix here: http://gist.github.com/230871
Will try patch against 4.5 first to not mess up the buildbot too much.
I believe this may be the same as bug #22896
*** Bug 22896 has been marked as a duplicate of this bug. ***
This was fixed in r51758
*** Bug 29458 has been marked as a duplicate of this bug. ***