It appears that both Google Chrome and Chromium ignore the query string subset=all when selecting a font from the google font directory. This leads to the somewhat counterintuitive result that the display of a Google font directory font may be significantly worse on a Google browser than on other browsers, including Firefox or Safari.

Compare the following screenshots from http://unifraktur.sourceforge.net/ where Google Chrome and Chromium fail to properly display the character ſ:

OK?	Screenshot	Browser
No		Google Chrome 44 on OS X 10.10
Yes		Firefox 40 on OS X 10.10
Yes		Safari 8.0 on OS X 10.10

The character ſ is supposed to be included by requesting the font with subset=all in the corresponding CSS file (see http://unifraktur.sourceforge.net/html-files/unifraktur.css):

@import url('http://fonts.googleapis.com/css?family=UnifrakturMaguntia|UnifrakturCook:bold&subset=all');

PS:

I do not know whether this is related to Chrome/Chromium's unicode-range ability or to #64.

Of course, it does not only affect whacky fraktur fonts, but any font with a wide character range, e.g. the font Judson that is intended to cover characters found in African languages:

OK?	Screenshot	Browser
No		Chromium 44 on Ubuntu 15.04
Yes		Firefox 40 on Ubuntu 15.04
Yes		Midori 0.4 on Ubuntu 15.04

Or the font Voces that is intended to cover IPA characters:

OK?	Screenshot	Browser
No		Chromium 44 on Ubuntu 15.04
Yes		Firefox 40 on Ubuntu 15.04
Yes		Midori 0.4 on Ubuntu 15.04

Here is a testpage that includes more extensive samples: Google Chrome and Chromium ignore "subset=all".