Bug 1577171 - Remove duplicated logic from Stylo's Gecko wrapper. r=emilio

Stylo's Gecko wrapper duplicated some logic from the C++ side so
that the Rust compiler would be able to optimize better. Now that
we have xLTO, this kind of manual inlining should not be neccessary
anymore.

Differential Revision: https://phabricator.services.mozilla.com/D43765

--HG--
extra : moz-landing-system : lando

layout/style/GeckoBindings.cpp

@@ -153,6 +153,10 @@ const Element* Gecko_GetMarkerPseudo(const Element* aElement) {
   return nsLayoutUtils::GetMarkerPseudo(aElement);
 }
 
+bool Gecko_IsInAnonymousSubtree(const Element* aElement) {
+  return aElement->IsInAnonymousSubtree();
+}
+
 nsTArray<nsIContent*>* Gecko_GetAnonymousContentForElement(
     const Element* aElement) {
   nsIAnonymousContentCreator* ac = do_QueryFrame(aElement->GetPrimaryFrame());

layout/style/GeckoBindings.h

@@ -81,6 +81,8 @@ const mozilla::dom::Element* Gecko_GetBeforeOrAfterPseudo(
 const mozilla::dom::Element* Gecko_GetMarkerPseudo(
     const mozilla::dom::Element*);
 
+bool Gecko_IsInAnonymousSubtree(const mozilla::dom::Element*);
+
 nsTArray<nsIContent*>* Gecko_GetAnonymousContentForElement(
     const mozilla::dom::Element*);
 void Gecko_DestroyAnonymousContentList(nsTArray<nsIContent*>* anon_content);

servo/components/style/gecko/wrapper.rs

@@ -706,44 +706,6 @@ impl<'le> GeckoElement<'le> {
         !self.xbl_binding_with_content().is_none()
     }
 
-    /// This duplicates the logic in Gecko's virtual nsINode::GetBindingParent
-    /// function, which only has two implementations: one for XUL elements, and
-    /// one for other elements.
-    ///
-    /// We just hard code in our knowledge of those two implementations here.
-    fn xbl_binding_parent(&self) -> Option<Self> {
-        if self.is_xul_element() {
-            // FIXME(heycam): Having trouble with bindgen on nsXULElement,
-            // where the binding parent is stored in a member variable
-            // rather than in slots.  So just get it through FFI for now.
-            unsafe {
-                bindings::Gecko_GetBindingParent(self.0)
-                    .as_ref()
-                    .map(GeckoElement)
-            }
-        } else {
-            let binding_parent =
-                unsafe { self.non_xul_xbl_binding_parent().as_ref() }.map(GeckoElement);
-
-            debug_assert!(
-                binding_parent ==
-                    unsafe {
-                        bindings::Gecko_GetBindingParent(self.0)
-                            .as_ref()
-                            .map(GeckoElement)
-                    }
-            );
-            binding_parent
-        }
-    }
-
-    #[inline]
-    fn non_xul_xbl_binding_parent(&self) -> *mut RawGeckoElement {
-        debug_assert!(!self.is_xul_element());
-        self.extended_slots()
-            .map_or(ptr::null_mut(), |slots| slots._base.mBindingParent.mRawPtr)
-    }
-
     #[inline]
     fn namespace_id(&self) -> i32 {
         self.as_node().node_info().mInner.mNamespaceID
@@ -865,19 +827,11 @@ impl<'le> GeckoElement<'le> {
         return self.flags() & (NODE_IS_NATIVE_ANONYMOUS_ROOT as u32) != 0;
     }
 
-    /// This logic is duplicated in Gecko's nsIContent::IsInAnonymousSubtree.
     #[inline]
     fn is_in_anonymous_subtree(&self) -> bool {
-        if self.is_in_native_anonymous_subtree() {
-            return true;
+        unsafe {
+            bindings::Gecko_IsInAnonymousSubtree(self.0)
         }
-
-        let binding_parent = match self.xbl_binding_parent() {
-            Some(p) => p,
-            None => return false,
-        };
-
-        binding_parent.shadow_root().is_none()
     }
 
     /// Returns true if this node is the shadow root of an use-element shadow tree.