Parse @font-feature-values at-rule

Part 2 of supporting font-variant-alternates. Parse @font-feature-values
at-rule. Exercise code in basic CSSParserImplTest test. This change does
not yet store rules in the style engine.

In this change, the CSSOM wrapper retrieval for
StyleRuleFontFeatureValues intentionally returns nullptr in the interest
of keeping this CL small, which changes the WPT test result for
now. CSSOM Implementation follows in the next part of the series.

Bug: 716567
Change-Id: Ie67ddf0ad068831c273ab6f5e1befeaf3d7c9988
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4055526
Commit-Queue: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1076713}

third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom

@@ -3742,6 +3742,12 @@ enum WebFeature {
   kSoftNavigationHeuristics = 4401,
   kMathMLMathElement = 4402,
   kMathMLMathElementInDocument = 4403,
+  kCSSAtRuleStylistic = 4404,
+  kCSSAtRuleStyleset = 4405,
+  kCSSAtRuleCharacterVariant = 4406,
+  kCSSAtRuleSwash = 4407 ,
+  kCSSAtRuleOrnaments = 4408,
+  kCSSAtRuleAnnotation = 4409,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/core/css/build.gni

@@ -661,6 +661,8 @@ blink_core_sources_css = [
   "style_rule_css_style_declaration.h",
   "style_rule_font_palette_values.cc",
   "style_rule_font_palette_values.h",
+  "style_rule_font_feature_values.cc",
+  "style_rule_font_feature_values.h",
   "style_rule_import.cc",
   "style_rule_import.h",
   "style_rule_keyframe.cc",

third_party/blink/renderer/core/css/css_rule.h

@@ -62,6 +62,7 @@ class CORE_EXPORT CSSRule : public ScriptWrappable {
     kNamespaceRule = 10,
     kCounterStyleRule = 11,
     kSupportsRule = 12,
+    kFontFeatureValuesRule = 14,
     kViewportRule = 15,
     // CSSOM constants are deprecated [1], and there will be no new
     // web-exposed values.
@@ -77,6 +78,7 @@ class CORE_EXPORT CSSRule : public ScriptWrappable {
     kScopeRule = 21,
     kPositionFallbackRule = 22,
     kTryRule = 23,
+    kFontFeatureRule = 24,
   };
 
   virtual Type GetType() const = 0;

third_party/blink/renderer/core/css/parser/at_rule_descriptor_parser.cc

@@ -269,6 +269,8 @@ CSSValue* ConsumeDescriptor(StyleRule::RuleType rule_type,
     case StyleRule::kPage:
     case StyleRule::kKeyframes:
     case StyleRule::kKeyframe:
+    case StyleRule::kFontFeatureValues:
+    case StyleRule::kFontFeature:
     case StyleRule::kLayerBlock:
     case StyleRule::kLayerStatement:
     case StyleRule::kNamespace:

third_party/blink/renderer/core/css/parser/css_at_rule_id.cc

@@ -22,6 +22,41 @@ CSSAtRuleID CssAtRuleID(StringView name) {
       return CSSAtRuleID::kCSSAtRuleFontPaletteValues;
     return CSSAtRuleID::kCSSAtRuleInvalid;
   }
+  if (EqualIgnoringASCIICase(name, "font-feature-values")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleFontFeatureValues;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "stylistic")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleStylistic;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "styleset")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleStyleset;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "character-variant")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleCharacterVariant;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "swash")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleSwash;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "ornaments")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleOrnaments;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
+  if (EqualIgnoringASCIICase(name, "annotation")) {
+    if (RuntimeEnabledFeatures::FontVariantAlternatesEnabled())
+      return CSSAtRuleID::kCSSAtRuleAnnotation;
+    return CSSAtRuleID::kCSSAtRuleInvalid;
+  }
   if (EqualIgnoringASCIICase(name, "import"))
     return CSSAtRuleID::kCSSAtRuleImport;
   if (EqualIgnoringASCIICase(name, "keyframes"))
@@ -72,12 +107,18 @@ namespace {
 
 absl::optional<WebFeature> AtRuleFeature(CSSAtRuleID rule_id) {
   switch (rule_id) {
+    case CSSAtRuleID::kCSSAtRuleAnnotation:
+      return WebFeature::kCSSAtRuleAnnotation;
     case CSSAtRuleID::kCSSAtRuleCharset:
       return WebFeature::kCSSAtRuleCharset;
+    case CSSAtRuleID::kCSSAtRuleCharacterVariant:
+      return WebFeature::kCSSAtRuleCharacterVariant;
     case CSSAtRuleID::kCSSAtRuleFontFace:
       return WebFeature::kCSSAtRuleFontFace;
     case CSSAtRuleID::kCSSAtRuleFontPaletteValues:
       return WebFeature::kCSSAtRuleFontPaletteValues;
+    case CSSAtRuleID::kCSSAtRuleFontFeatureValues:
+      return WebFeature::kCSSAtRuleFontFeatureValues;
     case CSSAtRuleID::kCSSAtRuleImport:
       return WebFeature::kCSSAtRuleImport;
     case CSSAtRuleID::kCSSAtRuleKeyframes:
@@ -96,8 +137,16 @@ absl::optional<WebFeature> AtRuleFeature(CSSAtRuleID rule_id) {
       return WebFeature::kCSSAtRuleContainer;
     case CSSAtRuleID::kCSSAtRuleCounterStyle:
       return WebFeature::kCSSAtRuleCounterStyle;
+    case CSSAtRuleID::kCSSAtRuleOrnaments:
+      return WebFeature::kCSSAtRuleOrnaments;
     case CSSAtRuleID::kCSSAtRuleScope:
       return WebFeature::kCSSAtRuleScope;
+    case CSSAtRuleID::kCSSAtRuleStyleset:
+      return WebFeature::kCSSAtRuleStylistic;
+    case CSSAtRuleID::kCSSAtRuleStylistic:
+      return WebFeature::kCSSAtRuleStylistic;
+    case CSSAtRuleID::kCSSAtRuleSwash:
+      return WebFeature::kCSSAtRuleSwash;
     case CSSAtRuleID::kCSSAtRuleScrollTimeline:
       return WebFeature::kCSSAtRuleScrollTimeline;
     case CSSAtRuleID::kCSSAtRuleSupports:

third_party/blink/renderer/core/css/parser/css_at_rule_id.h

@@ -31,6 +31,14 @@ enum class CSSAtRuleID {
   kCSSAtRuleSupports,
   kCSSAtRuleTry,
   kCSSAtRuleWebkitKeyframes,
+  // Font-feature-values related at-rule ids below:
+  kCSSAtRuleAnnotation,
+  kCSSAtRuleCharacterVariant,
+  kCSSAtRuleFontFeatureValues,
+  kCSSAtRuleOrnaments,
+  kCSSAtRuleStylistic,
+  kCSSAtRuleStyleset,
+  kCSSAtRuleSwash
 };
 
 CSSAtRuleID CssAtRuleID(StringView name);