Auto merge of #15360 - atheed:font-weight-keyword, r=emilio

Ensured all font-weight keywords are preserved until computed-value time

Fixed the serialization of `font-weight` keywords (i.e. `bold`, `normal`, etc.) to ensure that Servo preserves the keyword until computed-value time (just as other major browsers do).

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #15337

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- [X] There are tests for these changes

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tests/unit/style/parsing/font.rs

@@ -6,7 +6,7 @@ use cssparser::Parser;
 use media_queries::CSSErrorReporterTest;
 use servo_url::ServoUrl;
 use style::parser::ParserContext;
-use style::properties::longhands::font_feature_settings;
+use style::properties::longhands::{font_feature_settings, font_weight};
 use style::properties::longhands::font_feature_settings::computed_value;
 use style::properties::longhands::font_feature_settings::computed_value::FeatureTagValue;
 use style::stylesheets::Origin;
@@ -98,6 +98,21 @@ fn font_language_override_should_parse_properly() {
     assert_eq!(danish, SpecifiedValue::Override("DAN".to_string()));
 }
 
+#[test]
+fn font_weight_keyword_should_preserve_keyword() {
+    use style::properties::longhands::font_weight::SpecifiedValue;
+
+    let url = ServoUrl::parse("http://localhost").unwrap();
+    let context = ParserContext::new(Origin::Author, &url, Box::new(CSSErrorReporterTest));
+    let mut parser = Parser::new("normal");
+    let result = font_weight::parse(&context, &mut parser);
+    assert_eq!(result.unwrap(), SpecifiedValue::Normal);
+
+    let mut parser = Parser::new("bold");
+    let result = font_weight::parse(&context, &mut parser);
+    assert_eq!(result.unwrap(), SpecifiedValue::Bold);
+}
+
 #[test]
 #[should_panic]
 fn font_language_override_should_fail_on_empty_str() {

tests/wpt/metadata-css/cssom-1_dev/html/index-002.htm.ini

@@ -33,6 +33,3 @@
   [list is expected to be list-style: circle inside;]
     expected: FAIL
 
-  [font-family is expected to be font-family: sans-serif; line-height: 2em; font-size: 3em; font-style: italic; font-weight: bold;]
-    expected: FAIL
-