nsCSSFontFaceStyleDecl::GetPropertyValue needs serialization code for the new -moz-font-feature-settings and -moz-font-language-override properties. nsCSSRules.cpp: In member function ‘nsresult nsCSSFontFaceStyleDecl::GetPropertyValue(nsCSSFontDesc, nsAString_internal&) const’: nsCSSRules.cpp:1613: warning: enumeration value ‘eCSSFontDesc_FontFeatureSettings’ not handled in switch nsCSSRules.cpp:1613: warning: enumeration value ‘eCSSFontDesc_FontLanguageOverride’ not handled in switch

It looks like we can handle these exactly like the font-family descriptor here, I think. I've also added some basic tests to test_font_face_parser.html to verify that these descriptors are supported.

Comment on attachment 465613 [details] [diff] [review] patch, v1 - add serialization support for new @font-face descriptors Close, but not quite; these two properties can also be eCSSUnit_Normal. That would trigger the assertion in this case. That said, I think the ideal thing to do here would be to have an array of properties somewhere that lines up with the enum values in nsCSSFontDesc (with eCSSProperty_UNKNOWN for src), and then use the code that's used here for _style, _weight, etc. for all descriptors except Src. That code is nice because it's reasonably general and should handle future changes, etc., without people noticing the issue here.

(And you should add a test of 'normal' to your tests, too.)

I think both family and src need to be an exception, actually; family has a eCSSUnit_String vs. eCSSUnit_Families issue.

Or it's ok if you just add two more cases like the existing Style/Weight/Stretch cases.

Comment on attachment 467401 [details] [diff] [review] patch, v2 - updated as per comment 5 r=dbaron

Comment on attachment 467401 [details] [diff] [review] patch, v2 - updated as per comment 5 Requesting approval to land this on trunk. It's basically a missing piece of the CSS font feature support that already landed in bug 511339. There should be no risk to any other aspect of functionality.