Reland "Fix case of incorrect removal of dir=auto state in HTMLElemen…

…t::OnDirAttrChanged."

This is a reland of commit 2de8c4d

Original change's description:
> Fix case of incorrect removal of dir=auto state in HTMLElement::OnDirAttrChanged.
>
> When a dir=auto attribute is removed, we might still need to be in the
> ancestor-or-self-has-dir-auto state because of an ancestor.  This state
> is needed to know when we need to handle auto direction changes for
> dynamic changes to text.
>
> Bug: 576815
> Change-Id: I5d8cd262a165962fbd0bc14aa0de8bd16c970400
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4812429
> Commit-Queue: Di Zhang <dizhangg@chromium.org>
> Commit-Queue: David Baron <dbaron@chromium.org>
> Reviewed-by: Di Zhang <dizhangg@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1209530}

Bug: 576815
Change-Id: Ic490f7cf61efcea32f981e9e55c00cc5f6ef2a46
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4939634
Reviewed-by: Di Zhang <dizhangg@chromium.org>
Auto-Submit: David Baron <dbaron@chromium.org>
Commit-Queue: Di Zhang <dizhangg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1209769}

third_party/blink/renderer/core/dom/element.h

@@ -1343,6 +1343,7 @@ class CORE_EXPORT Element : public ContainerNode, public Animatable {
   TextDirection ParentDirectionality() const;
   void AdjustDirectionalityIfNeededAfterChildrenChanged(
       const ChildrenChange& change);
+  bool RecalcSelfOrAncestorHasDirAuto();
   template <typename Traversal>
   absl::optional<TextDirection> ResolveAutoDirectionality(
       bool& is_deferred,
@@ -1496,7 +1497,6 @@ class CORE_EXPORT Element : public ContainerNode, public Animatable {
   }
 
   void RecomputeDirectionFromParent();
-  bool RecalcSelfOrAncestorHasDirAuto();
 
   ShadowRoot& CreateAndAttachShadowRoot(ShadowRootType);
 

third_party/blink/renderer/core/html/html_element.cc

@@ -3024,8 +3024,11 @@ void HTMLElement::OnDirAttrChanged(const AttributeModificationParams& params) {
   }
 
   if (is_old_auto && !is_new_auto) {
-    ClearSelfOrAncestorHasDirAutoAttribute();
-    UpdateDescendantHasDirAutoAttribute(false /* has_dir_auto */);
+    if (!RuntimeEnabledFeatures::CSSPseudoDirEnabled() ||
+        !RecalcSelfOrAncestorHasDirAuto()) {
+      ClearSelfOrAncestorHasDirAutoAttribute();
+      UpdateDescendantHasDirAutoAttribute(false /* has_dir_auto */);
+    }
   } else if (!is_old_auto && is_new_auto) {
     SetSelfOrAncestorHasDirAutoAttribute();
     UpdateDescendantHasDirAutoAttribute(true /* has_dir_auto */);

third_party/blink/web_tests/external/wpt/html/dom/elements/global-attributes/dir-assorted.window.js

@@ -63,3 +63,20 @@ test(() => {
   assert_true(ele.matches(":dir(ltr)"), "is LTR after change");
   assert_true(ele2.matches(":dir(ltr)"), "child is LTR after change");
 }, "Non-HTML element text contents influence dir=auto");
+
+test(() => {
+  const e1 = document.createElement("div");
+  e1.dir = "auto";
+  const e2 = document.createElement("div");
+  e2.dir = "auto";
+  e2.innerText = "A";
+  e1.append(e2);
+  assert_true(e1.matches(":dir(ltr)"), "parent is LTR before changes");
+  assert_true(e2.matches(":dir(ltr)"), "child is LTR before changes");
+  e2.removeAttribute("dir");
+  assert_true(e1.matches(":dir(ltr)"), "parent is LTR after removing dir attribute on child");
+  assert_true(e2.matches(":dir(ltr)"), "child is LTR after removing dir attribute on child");
+  e2.firstChild.data = "\u05D0";
+  assert_false(e1.matches(":dir(ltr)"), "parent is RTL after changing text in child");
+  assert_false(e2.matches(":dir(ltr)"), "child is RTL after changing text in child");
+}, "text changes apply to dir=auto on further ancestor after removing dir=auto from closer ancestor");