[css-fonts-4] Add font-variation-settings descriptor in @font-face

#1652

Author: litherum

css-fonts-4/Overview.bs

@@ -1921,7 +1921,7 @@ body { font-family: DroidSans; }
 </div>
 
 <h3 id="font-rend-desc">
-Font features: the 'font-variant' and 'font-feature-settings' descriptors</h3>
+Font features and variations: the 'font-variant', 'font-feature-settings', and 'font-variation-settings' descriptors</h3>
 
 <pre class='descdef'>
 Name: font-variant
@@ -1946,14 +1946,21 @@ Initial: normal
 For: @font-face
 </pre>
 
+<pre class='descdef'>
+Name: font-variation-settings
+Value: normal | [ <<string>> <<number>>] #
+Initial: normal
+For: @font-face
+</pre>
+
 These descriptors define initial settings that apply when the font defined by
 an <code>@font-face</code> rule is rendered.  They do not affect font selection.
 Values are identical to those defined for the corresponding
-'font-variant' and 'font-feature-settings' properties defined below
+'font-variant', 'font-feature-settings', and 'font-variation-settings' properties defined below
 except that the value 'inherit' is omitted.  When multiple font
-feature descriptors or properties are used, the cumulative effect on
+feature descriptors, properties, or variations are used, the cumulative effect on
 text rendering is detailed in the section
-<a href="#font-feature-resolution">Font Feature Resolution</a> below.
+<a href="#font-feature-variation-resolution">Font Feature and Variation Resolution</a> below.
 In cases where specific values define synthesized fallback for certain
 'font-variant' subproperties, the same synthesized fallback
 applies when used within those values are used with the
@@ -2685,29 +2692,32 @@ text run.
 	Then, the values applied in this step should be clamped (possibly again) to the values
 	that are supported by the font.
 
-3. If the font is defined via an ''@font-face'' rule, the font features
-	implied by the font-variant descriptor in the ''@font-face'' rule.
+3. If the font is defined via an ''@font-face'' rule, the font variations
+	implied by the 'font-variation-settings' descriptor in the ''@font-face'' rule.
 
 4. If the font is defined via an ''@font-face'' rule, the font features
-	implied by the font-feature-settings descriptor in the ''@font-face'' rule.
+	implied by the 'font-feature-settings' descriptor in the ''@font-face'' rule.
+
+5. If the font is defined via an ''@font-face'' rule, the font features
+	implied by the 'font-feature-settings' descriptor in the ''@font-face'' rule.
 
-5. Font variations implied by the value of the 'font-optical-sizing' property.
+6. Font variations implied by the value of the 'font-optical-sizing' property.
 
-6. Font features implied by the value of the 'font-variant' property,
+7. Font features implied by the value of the 'font-variant' property,
 	the related 'font-variant' subproperties and any other CSS property
 	that uses OpenType features (e.g. the 'font-kerning' property).
 
 	<!-- other CSS props override 'font-variant' but not 'font-feature-settings' -->
 	<!-- http://lists.w3.org/Archives/Public/www-style/2013Aug/0110.html -->
 
-7. Feature settings determined by properties other than 'font-variant' or
+8. Feature settings determined by properties other than 'font-variant' or
 	'font-feature-settings'. For example, setting a
 	non-default value for the 'letter-spacing' property disables common ligatures.
 
-8. Font variations implied by the value of the 'font-variation-settings' property.
+9. Font variations implied by the value of the 'font-variation-settings' property.
 	These values should be clamped to the values that are supported by the font.
 
-9. Font features implied by the value of 'font-feature-settings' property.
+10. Font features implied by the value of 'font-feature-settings' property.
 
 This ordering allows authors to set up a general set of defaults
 for fonts within their ''@font-face'' rules, then override them with