Bug 1854809 - Include quotes in AtomString CSS serialization r=emilio

The serialization of `AtomString` should include quotes itself
rather than users of it having to do so themselves.

Differential Revision: https://phabricator.services.mozilla.com/D189050

servo/components/selectors/CHANGES.md

@@ -0,0 +1 @@
+- `parser.rs` no longer wraps values in quotes (`"..."`) but expects their `to_css` impl to already wrap it ([Gecko Bug 1854809](https://bugzilla.mozilla.org/show_bug.cgi?id=1854809))

servo/components/selectors/parser.rs

@@ -2291,9 +2291,7 @@ impl<Impl: SelectorImpl> ToCss for Component<Impl> {
                 dest.write_char('[')?;
                 local_name.to_css(dest)?;
                 operator.to_css(dest)?;
-                dest.write_char('"')?;
                 value.to_css(dest)?;
-                dest.write_char('"')?;
                 match case_sensitivity {
                     ParsedCaseSensitivity::CaseSensitive |
                     ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {},
@@ -2397,9 +2395,7 @@ impl<Impl: SelectorImpl> ToCss for AttrSelectorWithOptionalNamespace<Impl> {
                 ref value,
             } => {
                 operator.to_css(dest)?;
-                dest.write_char('"')?;
                 value.to_css(dest)?;
-                dest.write_char('"')?;
                 match case_sensitivity {
                     ParsedCaseSensitivity::CaseSensitive |
                     ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument => {},

servo/components/style/values/mod.rs

@@ -177,15 +177,18 @@ impl cssparser::ToCss for AtomString {
     where
         W: Write,
     {
+        // Wrap in quotes to form a string literal
+        dest.write_char('"')?;
         #[cfg(feature = "servo")]
         {
-            cssparser::CssStringWriter::new(dest).write_str(self.as_ref())
+            cssparser::CssStringWriter::new(dest).write_str(self.as_ref())?;
         }
         #[cfg(feature = "gecko")]
         {
             self.0
-                .with_str(|s| cssparser::CssStringWriter::new(dest).write_str(s))
+                .with_str(|s| cssparser::CssStringWriter::new(dest).write_str(s))?;
         }
+        dest.write_char('"')
     }
 }
 

servo/components/style/values/specified/mod.rs

@@ -966,10 +966,8 @@ impl ToCss for Attr {
         serialize_atom_identifier(&self.attribute, dest)?;
 
         if !self.fallback.is_empty() {
-            // Fallback will always be a string value for now, so always wrap in "..."
+            dest.write_str(", ")?;
-            dest.write_str(", \"")?;
             self.fallback.to_css(dest)?;
-            dest.write_char('"')?;
         }
 
         dest.write_char(')')