Add FFI for calling Servo's add and accumulate methods on animation values

components/style/gecko/generated/bindings.rs

@@ -2185,6 +2185,17 @@ extern "C" {
                                                     RawServoAnimationValueBorrowed)
      -> bool;
 }
+extern "C" {
+    pub fn Servo_AnimationValues_Add(a: RawServoAnimationValueBorrowed,
+                                     b: RawServoAnimationValueBorrowed)
+     -> RawServoAnimationValueStrong;
+}
+extern "C" {
+    pub fn Servo_AnimationValues_Accumulate(a: RawServoAnimationValueBorrowed,
+                                            b: RawServoAnimationValueBorrowed,
+                                            count: u64)
+     -> RawServoAnimationValueStrong;
+}
 extern "C" {
     pub fn Servo_AnimationValues_GetZeroValue(value_to_match:
                                                   RawServoAnimationValueBorrowed)

ports/geckolib/glue.rs

@@ -313,6 +313,35 @@ pub extern "C" fn Servo_AnimationValues_IsInterpolable(from: RawServoAnimationVa
     from_value.interpolate(to_value, 0.5).is_ok()
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_AnimationValues_Add(a: RawServoAnimationValueBorrowed,
+                                            b: RawServoAnimationValueBorrowed)
+     -> RawServoAnimationValueStrong
+{
+    let a_value = AnimationValue::as_arc(&a);
+    let b_value = AnimationValue::as_arc(&b);
+    if let Ok(value) = a_value.add(b_value) {
+        Arc::new(value).into_strong()
+    } else {
+        RawServoAnimationValueStrong::null()
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_AnimationValues_Accumulate(a: RawServoAnimationValueBorrowed,
+                                                   b: RawServoAnimationValueBorrowed,
+                                                   count: u64)
+     -> RawServoAnimationValueStrong
+{
+    let a_value = AnimationValue::as_arc(&a);
+    let b_value = AnimationValue::as_arc(&b);
+    if let Ok(value) = a_value.accumulate(b_value, count) {
+        Arc::new(value).into_strong()
+    } else {
+        RawServoAnimationValueStrong::null()
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_AnimationValues_GetZeroValue(
     value_to_match: RawServoAnimationValueBorrowed)