From 88173648e3f2a7f772fdfbaa8643fa02ce0fed50 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 14 Mar 2022 20:23:18 +0100
Subject: [PATCH] LibWeb: Create HTMLInputElement UA shadow tree when inserted
 into DOM

Previously, we were creating a user-agent shadow tree when constructing
a layout tree. This meant that we did DOM manipulation (and consequently
style invalidation) during layout tree construction, which made things
very hard to reason about in Layout::TreeBuilder.

Simply everything by simply creating the UA shadow tree when the input
element inserted into a parent node instead.
---
 Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp | 6 +++++-
 Userland/Libraries/LibWeb/HTML/HTMLInputElement.h   | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
index cf7bd2c407d..27066a9544c 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
@@ -64,7 +64,6 @@ RefPtr<Layout::Node> HTMLInputElement::create_layout_node(NonnullRefPtr<CSS::Sty
     if (type() == "radio")
         return adopt_ref(*new Layout::RadioButton(document(), *this, move(style)));
 
-    create_shadow_tree_if_needed();
     auto layout_node = adopt_ref(*new Layout::BlockContainer(document(), this, move(style)));
     layout_node->set_inline(true);
     return layout_node;
@@ -284,4 +283,9 @@ String HTMLInputElement::value_sanitization_algorithm(String value) const
     return value;
 }
 
+void HTMLInputElement::inserted()
+{
+    create_shadow_tree_if_needed();
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
index 7d5e6b2ec1b..1bad7acd934 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
@@ -100,6 +100,8 @@ public:
     // https://html.spec.whatwg.org/multipage/forms.html#category-label
     virtual bool is_labelable() const override { return type_state() != TypeAttributeState::Hidden; }
 
+    virtual void inserted() override;
+
 private:
     // ^DOM::EventTarget
     virtual void did_receive_focus() override;