stylo: Remove Servo_Element_ShouldTraverse.

components/style/gecko_bindings/bindings.rs

@@ -1129,10 +1129,6 @@ extern "C" {
 extern "C" {
     pub fn Servo_Element_ClearData(node: RawGeckoElementBorrowed);
 }
-extern "C" {
-    pub fn Servo_Element_ShouldTraverse(node: RawGeckoElementBorrowed)
-     -> bool;
-}
 extern "C" {
     pub fn Servo_StyleSheet_Empty(parsing_mode: SheetParsingMode)
      -> RawServoStyleSheetStrong;

ports/geckolib/glue.rs

@@ -347,24 +347,6 @@ pub extern "C" fn Servo_Element_ClearData(element: RawGeckoElementBorrowed) -> (
     GeckoElement(element).clear_data();
 }
 
-#[no_mangle]
-pub extern "C" fn Servo_Element_ShouldTraverse(element: RawGeckoElementBorrowed) -> bool {
-    let element = GeckoElement(element);
-    debug_assert!(!element.has_dirty_descendants(),
-                  "only call Servo_Element_ShouldTraverse if you know the element \
-                   does not have dirty descendants");
-    let result = match element.borrow_data() {
-        // Note that we check for has_restyle here rather than has_current_styles,
-        // because we also want the traversal code to trigger if there's restyle
-        // damage. We really only need the Gecko post-traversal in that case, so
-        // the servo traversal will be a no-op, but it's cheap enough that we
-        // don't bother distinguishing the two cases.
-        Some(d) => !d.has_styles() || d.has_restyle(),
-        None => true,
-    };
-    result
-}
-
 #[no_mangle]
 pub extern "C" fn Servo_StyleSheet_Empty(mode: SheetParsingMode) -> RawServoStyleSheetStrong {
     let url = ServoUrl::parse("about:blank").unwrap();