[css-font-loading] Harmonize FontFace with @font-face, adding variationSettings and fontDisplay.

Author: tabatkins

css-font-loading-3/Overview.bs

@@ -86,6 +86,8 @@ The <code>FontFace</code> Interface</h2>
 			CSSOMString unicodeRange = "U+0-10FFFF";
 			CSSOMString variant = "normal";
 			CSSOMString featureSettings = "normal";
+			CSSOMString variationSettings = "normal";
+			CSSOMString fontDisplay = "auto";
 		};
 
 		enum FontFaceLoadStatus { "unloaded", "loading", "loaded", "error" };
@@ -101,6 +103,8 @@ The <code>FontFace</code> Interface</h2>
 			attribute CSSOMString unicodeRange;
 			attribute CSSOMString variant;
 			attribute CSSOMString featureSettings;
+			attribute CSSOMString variationSettings;
+			attribute CSSOMString fontDisplay;
 
 			readonly attribute FontFaceLoadStatus status;
 
@@ -137,13 +141,15 @@ The <code>FontFace</code> Interface</h2>
 
 			On getting, return the string associated with this attribute.
 
-			On setting, parse the string according to the grammar for the CSS ''@font-face'' rule.
+			On setting, [=CSS/parse=] the string according to the grammar for the corresponding ''@font-face'' descriptor.
 			If it does not match the grammar,
-			throw a SyntaxError;
+			throw a {{SyntaxError}};
 			otherwise, set the attribute to the serialization of the parsed value.
 
 		: <dfn>variant</dfn>
 		: <dfn>featureSettings</dfn>
+		: <dfn>variationSettings</dfn>
+		: <dfn>fontDisplay</dfn>
 		::
 			These attributes have the same meaning,
 			and are parsed the same as,
@@ -155,9 +161,9 @@ The <code>FontFace</code> Interface</h2>
 
 			On getting, return the string associated with this attribute.
 
-			On setting, parse the string according to the grammar for the CSS ''@font-face'' rule.
+			On setting, [=CSS/parse=] the string according to the grammar for the corresponding ''@font-face'' descriptor.
 			If it does not match the grammar,
-			throw a SyntaxError;
+			throw a {{SyntaxError}};
 			otherwise, set the attribute to the serialization of the parsed value.
 
 		: <dfn>status</dfn>
@@ -217,7 +223,7 @@ The Constructor</h3>
 		Set <var>font face's</var> {{FontFace/status}} attribute to <code>"unloaded"</code>,
 		Set its internal {{[[FontStatusPromise]]}} slot to a fresh pending {{Promise}} object.
 
-		Parse the {{family!!argument}} argument,
+		[=CSS/Parse=] the {{family!!argument}} argument,
 		and the members of the {{descriptors!!argument}} argument,
 		according to the grammars of the corresponding descriptors of the CSS ''@font-face'' rule.
 		If the {{source!!argument}} argument is a {{CSSOMString}},