From e26e85a3d24d9e570a35ac20bf043d6df47f3d0f Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 27 Sep 2021 16:02:13 +0200
Subject: [PATCH] LibWeb: Support Document.hidden and Document.visibilityState

These just act as if the document is always visible for now.
---
 Userland/Libraries/LibWeb/DOM/Document.cpp | 12 ++++++++++++
 Userland/Libraries/LibWeb/DOM/Document.h   |  3 +++
 Userland/Libraries/LibWeb/DOM/Document.idl |  3 +++
 3 files changed, 18 insertions(+)

diff --git a/Userland/Libraries/LibWeb/DOM/Document.cpp b/Userland/Libraries/LibWeb/DOM/Document.cpp
index 3c1dd8a464..875a36e0a4 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Document.cpp
@@ -1062,4 +1062,16 @@ Bindings::LocationObject* Document::location()
     return window().wrapper()->location_object();
 }
 
+// https://w3c.github.io/page-visibility/#hidden-attribute
+bool Document::hidden() const
+{
+    return false;
+}
+
+// https://w3c.github.io/page-visibility/#visibilitystate-attribute
+String Document::visibility_state() const
+{
+    return hidden() ? "hidden" : "visible";
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/DOM/Document.h b/Userland/Libraries/LibWeb/DOM/Document.h
index 27b2f45223..dfa07c1b05 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.h
+++ b/Userland/Libraries/LibWeb/DOM/Document.h
@@ -298,6 +298,9 @@ public:
     bool page_showing() const { return m_page_showing; }
     void set_page_showing(bool value) { m_page_showing = value; }
 
+    bool hidden() const;
+    String visibility_state() const;
+
 private:
     explicit Document(const AK::URL&);
 
diff --git a/Userland/Libraries/LibWeb/DOM/Document.idl b/Userland/Libraries/LibWeb/DOM/Document.idl
index dca0c8cfb7..c86cbc6799 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.idl
+++ b/Userland/Libraries/LibWeb/DOM/Document.idl
@@ -139,4 +139,7 @@ interface Document : Node {
     attribute EventHandler onwebkittransitionend;
     attribute EventHandler onwheel;
 
+    readonly boolean hidden;
+    readonly DOMString visibilityState;
+
 };