Support for @font-face unicode-range #913

I'd like to use Google's Noto fonts to improve language compatibility in my PDF exports. This would be part of software that would get run on lots of different servers over which I can't control what fonts are installed or not.

Here's how I've attempted to declare my fonts with @font-face, using the unicode-range to subset the font:

@font-face {
    font-family: 'Noto Sans';
    font-style: normal;
    font-weight: normal;
    src: local('Noto Sans'), local('NotoSans'), url(http://full/path/to/fonts/NotoSans-Regular.ttf) format('truetype');
    unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2212, U+2215, U+E0FF, U+EFFD, U+F000;
}
@font-face {
    font-family: 'Noto Sans';
    font-style: normal;
    font-weight: normal;
    src: local('Noto Sans Arabic'), local('NotoSansArabic'),    url(http://full/path/to/fonts/NotoNaskhArabic-Regular.ttf) format('truetype');
    unicode-range: U+060x-06Fx;
}

But this doesn't seem to be working. Arabic characters won't get displayed. And if I try to use a font stack to fall-back on a more workable font, it doesn't work:

<p style="font-family: 'Noto Sans', sans-serif;">من</p>

Is this a known issue? Or is there some way to get mixed-language documents that I'm missing? Thanks.