counter-reset defaults to 0, not 1.

components/style/properties.mako.rs

@@ -1305,6 +1305,10 @@ pub mod longhands {
         }
 
         pub fn parse(_: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue,()> {
+            parse_common(1, input)
+        }
+
+        pub fn parse_common(default_value: i32, input: &mut Parser) -> Result<SpecifiedValue,()> {
             if input.try(|input| input.expect_ident_matching("none")).is_ok() {
                 return Ok(SpecifiedValue(Vec::new()))
             }
@@ -1320,7 +1324,7 @@ pub mod longhands {
                     return Err(())
                 }
                 let counter_delta =
-                    input.try(|input| specified::parse_integer(input)).unwrap_or(1);
+                    input.try(|input| specified::parse_integer(input)).unwrap_or(default_value);
                 counters.push((counter_name, counter_delta))
             }
 
@@ -1334,7 +1338,11 @@ pub mod longhands {
 
     <%self:longhand name="counter-reset">
         pub use super::counter_increment::{SpecifiedValue, computed_value, get_initial_value};
-        pub use super::counter_increment::{parse};
+        use super::counter_increment::{parse_common};
+
+        pub fn parse(_: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue,()> {
+            parse_common(0, input)
+        }
     </%self:longhand>
 
     // CSS 2.1, Section 13 - Paged media

tests/wpt/mozilla/meta/css/test_variable_serialization_computed.html.ini

@@ -9,9 +9,6 @@
   [subtest #22 with `--a: var(--b,orange)var(--c); --c:red;`]
     expected: FAIL
 
-  [subtest #23 with `counter-reset: var(--a)red; --a:orange;`]
-    expected: FAIL
-
   [subtest #24 with `--a: var(--b)var(--c); --c:[c\]; --b:('ab`]
     expected: FAIL