Auto merge of #17364 - asajeffrey:script-paint-worklets-properties, r=jdm

Implement paint worklet properties

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This is the final PR to get basic paint worklet support. It adds support for paint worklet properties (https://drafts.css-houdini.org/css-paint-api/#paint-definition-input-properties). When a paint worklet is registered, it specifies a list of CSS properties, and is provided with their computed values when it is invoked.

This is a dependent PR:
* "Implemented paint worklets invoking worklet scripts" is #17239.
* "Implemented paint worklets rendering contexts" is #17326.

There should be tests added for this, hopefully the existing wpt houdini tests.

---
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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 #16839
- [x] There are tests for these changes

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components/style/servo/restyle_damage.rs

@@ -64,16 +64,7 @@ impl ServoRestyleDamage {
                                     new: &ServoComputedValues)
                                     -> StyleDifference {
         let damage = compute_damage(old, new);
-        // If computed values for custom properties changed, we should cascade these changes to
-        // children (custom properties are all inherited).
-        // https://www.w3.org/TR/css-variables/#defining-variables
-        // (With Properties & Values, not all custom properties will be inherited!)
-        let variable_values_changed = old.get_custom_properties() != new.get_custom_properties();
-        let change = if damage.is_empty() && !variable_values_changed {
-            StyleChange::Unchanged
-        } else {
-            StyleChange::Changed
-        };
+        let change = if damage.is_empty() { StyleChange::Unchanged } else { StyleChange::Changed };
         StyleDifference::new(damage, change)
     }
 
@@ -285,6 +276,13 @@ fn compute_damage(old: &ServoComputedValues, new: &ServoComputedValues) -> Servo
         get_inheritedbox.visibility
     ]);
 
+
+    // Paint worklets may depend on custom properties,
+    // so if they have changed we should repaint.
+    if old.get_custom_properties() != new.get_custom_properties() {
+        damage.insert(REPAINT);
+    }
+
     // If the layer requirements of this flow have changed due to the value
     // of the transform, then reflow is required to rebuild the layers.
     if old.transform_requires_layer() != new.transform_requires_layer() {