diff --git a/Libraries/LibHTML/Layout/LayoutNode.h b/Libraries/LibHTML/Layout/LayoutNode.h
index 78b77dd8504..38cd663d8de 100644
--- a/Libraries/LibHTML/Layout/LayoutNode.h
+++ b/Libraries/LibHTML/Layout/LayoutNode.h
@@ -81,8 +81,6 @@ public:
 
     void set_needs_display();
 
-    bool is_ancestor_of(const LayoutNode&) const;
-
     template<typename Callback>
     void for_each_fragment_of_this(Callback);
 
@@ -130,12 +128,3 @@ inline const LayoutNodeWithStyle* LayoutNode::parent() const
 {
     return static_cast<const LayoutNodeWithStyle*>(TreeNode<LayoutNode>::parent());
 }
-
-inline bool LayoutNode::is_ancestor_of(const LayoutNode& other) const
-{
-    for (auto* ancestor = other.parent(); ancestor; ancestor = ancestor->parent()) {
-        if (ancestor == this)
-            return true;
-    }
-    return false;
-}
diff --git a/Libraries/LibHTML/TreeNode.h b/Libraries/LibHTML/TreeNode.h
index 467ab83cfb3..f384dd0a1c5 100644
--- a/Libraries/LibHTML/TreeNode.h
+++ b/Libraries/LibHTML/TreeNode.h
@@ -33,6 +33,8 @@ public:
     const T* first_child() const { return m_first_child; }
     const T* last_child() const { return m_last_child; }
 
+    bool is_ancestor_of(const TreeNode&) const;
+
     void prepend_child(NonnullRefPtr<T> node, bool call_inserted_into = true);
     void append_child(NonnullRefPtr<T> node, bool call_inserted_into = true);
     void donate_all_children_to(T& node);
@@ -98,3 +100,14 @@ inline void TreeNode<T>::donate_all_children_to(T& node)
     m_first_child = nullptr;
     m_last_child = nullptr;
 }
+
+
+template<typename T>
+inline bool TreeNode<T>::is_ancestor_of(const TreeNode<T>& other) const
+{
+    for (auto* ancestor = other.parent(); ancestor; ancestor = ancestor->parent()) {
+        if (ancestor == this)
+            return true;
+    }
+    return false;
+}