Auto merge of #20351 - jwatt:master, r=emilio

Add Servo_Property_IsShorthand to geckolib/glue.rs

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components/style/properties/properties.mako.rs

@@ -1645,6 +1645,12 @@ impl PropertyId {
         }
     }
 
+    /// Returns true if the property is a shorthand or shorthand alias.
+    #[inline]
+    pub fn is_shorthand(&self) -> bool {
+        self.as_shorthand().is_ok()
+    }
+
     /// Given this property id, get it either as a shorthand or as a
     /// `PropertyDeclarationId`.
     pub fn as_shorthand(&self) -> Result<ShorthandId, PropertyDeclarationId> {

ports/geckolib/glue.rs

@@ -933,6 +933,23 @@ pub extern "C" fn Servo_ComputedValues_ExtractAnimationValue(
     }
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn Servo_Property_IsShorthand(
+    prop_name: *const nsACString,
+    found: *mut bool
+) -> bool {
+    let prop_id = PropertyId::parse(prop_name.as_ref().unwrap().as_str_unchecked());
+    let prop_id = match prop_id {
+        Ok(ref p) if p.enabled_for_all_content() => p,
+        _ => {
+            *found = false;
+            return false;
+        }
+    };
+    *found = true;
+    prop_id.is_shorthand()
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_Property_IsAnimatable(property: nsCSSPropertyID) -> bool {
     use style::properties::animated_properties;