Free fonts
Many people were upset that our tests depend on the non-free Microsoft web fonts. However, realistically, many web sites depend on these fonts and it is important that we test that our font metrics match the metrics used on those sites.
Separately, someone filed a bug saying we're using the wrong font on
ubuntuforums.org, a popular forum site. I took a look and found
their CSS says:
font-family: Verdana, Arial, Tahoma;
with no mention of their presumed intent that you fall back on a free sans-serif font if those fonts aren't available. So Chrome just falls back to the default font: a serifed one. (The interaction between CSS font fallback and fontconfig is complicated and ugly; hopefully I'll get to it another time.)
In conclusion, now I have a great example of the point I was making about non-free fonts.