From 04311ca7f115a33aa9891b7146407ed8fee3b726 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Wed, 9 Mar 2022 17:51:02 +0100
Subject: [PATCH] LibWeb: Flush pending layouts when accessing element resolved
 style

We were handing out stale values from window.getComputedStyle() objects
after the first layout.

Fix this by always updating layout on property access. This is not
necessary for all properties, but for now let's go with the simplest
approach to make it work correctly.
---
 Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
index 88b255fb65..296bc7ab6e 100644
--- a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
@@ -772,7 +772,8 @@ RefPtr<StyleValue> ResolvedCSSStyleDeclaration::style_value_for_property(Layout:
 
 Optional<StyleProperty> ResolvedCSSStyleDeclaration::property(PropertyID property_id) const
 {
-    const_cast<DOM::Document&>(m_element->document()).ensure_layout();
+    // FIXME: Only update layout if required to resolve the property we're accessing.
+    const_cast<DOM::Document&>(m_element->document()).update_layout();
 
     if (!m_element->layout_node()) {
         auto style = m_element->document().style_computer().compute_style(const_cast<DOM::Element&>(*m_element));