From 9949bc6c34e67b7e34b3eed6df7d165d019928f1 Mon Sep 17 00:00:00 2001
From: wolfbeast <mcwerewolf@gmail.com>
Date: Sat, 7 Jul 2018 11:24:38 +0200
Subject: [PATCH] Make the page visibility API pref-controlled.

This resolves #607.
---
 dom/webidl/Document.webidl  | 3 +++
 modules/libpref/init/all.js | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/dom/webidl/Document.webidl b/dom/webidl/Document.webidl
index 0b8c278fea..904b1fb779 100644
--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -277,8 +277,11 @@ partial interface Document {
 
 // https://w3c.github.io/page-visibility/#extensions-to-the-document-interface
 partial interface Document {
+  [Pref="dom.visibilityAPI.enabled"]
   readonly attribute boolean hidden;
+  [Pref="dom.visibilityAPI.enabled"]
   readonly attribute VisibilityState visibilityState;
+  [Pref="dom.visibilityAPI.enabled"]
            attribute EventHandler onvisibilitychange;
 };
 
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 3a955dc3df..9372451a28 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -155,6 +155,9 @@ pref("dom.select_events.textcontrols.enabled", true);
 pref("dom.select_events.textcontrols.enabled", false);
 #endif
 
+// Whether or not the document visbility API is enabled
+pref("dom.visibilityAPI.enabled", true);
+
 // Whether or not Web Workers are enabled.
 pref("dom.workers.enabled", true);