From 562744b21491aaecaea1ef09690ec9c587f68d19 Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Thu, 12 Mar 2026 10:00:04 +0100
Subject: [PATCH] Remove the Servo non-incremental layout feature

This isn't really used. Nowadays we always test incremental layout as
it's considered an essential feature of the functionining of Servo.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
---
 style/traversal.rs | 33 ++-------------------------------
 1 file changed, 2 insertions(+), 31 deletions(-)

diff --git a/style/traversal.rs b/style/traversal.rs
index b80fd1dc73..d0ac0294b1 100644
--- a/style/traversal.rs
+++ b/style/traversal.rs
@@ -52,27 +52,6 @@ impl<E: TElement> PreTraverseToken<E> {
     }
 }
 
-/// A global variable holding the state of
-/// `is_servo_nonincremental_layout()`.
-/// See [#22854](https://github.com/servo/servo/issues/22854).
-#[cfg(feature = "servo")]
-pub static IS_SERVO_NONINCREMENTAL_LAYOUT: std::sync::atomic::AtomicBool =
-    std::sync::atomic::AtomicBool::new(false);
-
-#[cfg(feature = "servo")]
-#[inline]
-fn is_servo_nonincremental_layout() -> bool {
-    use std::sync::atomic::Ordering;
-
-    IS_SERVO_NONINCREMENTAL_LAYOUT.load(Ordering::Relaxed)
-}
-
-#[cfg(not(feature = "servo"))]
-#[inline]
-fn is_servo_nonincremental_layout() -> bool {
-    false
-}
-
 /// A DOM Traversal trait, that is used to generically implement styling for
 /// Gecko and Servo.
 pub trait DomTraversal<E: TElement>: Sync {
@@ -219,11 +198,6 @@ pub trait DomTraversal<E: TElement>: Sync {
             el, traversal_flags, data
         );
 
-        // Non-incremental layout visits every node.
-        if is_servo_nonincremental_layout() {
-            return true;
-        }
-
         // Unwrap the data.
         let data = match data {
             Some(d) if d.has_styles() => d,
@@ -513,8 +487,7 @@ pub fn recalc_style_at<E, D, F>(
     // We only do this if we're not a display: none root, since in that case
     // it's useless to style children.
     let mut traverse_children = has_dirty_descendants_for_this_restyle
-        || !propagated_hint.is_empty()
-        || is_servo_nonincremental_layout();
+        || !propagated_hint.is_empty();
 
     traverse_children = traverse_children && !data.styles.is_display_none();
 
@@ -759,9 +732,7 @@ fn note_children<E, D, F>(
         let child = match child_node.as_element() {
             Some(el) => el,
             None => {
-                if is_servo_nonincremental_layout()
-                    || D::text_node_needs_traversal(child_node, data)
-                {
+                if D::text_node_needs_traversal(child_node, data) {
                     note_child(child_node);
                 }
                 continue;