From b5e156f5c2f5d4e594be5e55f92acae4e6b52908 Mon Sep 17 00:00:00 2001
From: Eitan Isaacson <eitan@monotonous.org>
Date: Fri, 26 May 2017 15:10:57 -0700
Subject: [PATCH] Bug 1368103 - Use DOM doc visibilityState to determine if a
 tab is hidden. r=surkov

---
 accessible/generic/Accessible.cpp  | 4 ++++
 accessible/generic/DocAccessible.h | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/accessible/generic/Accessible.cpp b/accessible/generic/Accessible.cpp
index 868b672e1793..690d1608cec7 100644
--- a/accessible/generic/Accessible.cpp
+++ b/accessible/generic/Accessible.cpp
@@ -335,6 +335,10 @@ Accessible::VisibilityState()
   if (!frame->StyleVisibility()->IsVisible())
     return states::INVISIBLE;
 
+  // Offscreen state if the document's visibility state is not visible.
+  if (Document()->IsHidden())
+    return states::OFFSCREEN;
+
   nsIFrame* curFrame = frame;
   do {
     nsView* view = curFrame->GetView();
diff --git a/accessible/generic/DocAccessible.h b/accessible/generic/DocAccessible.h
index 2977fff4b1ed..885cb8c987b0 100644
--- a/accessible/generic/DocAccessible.h
+++ b/accessible/generic/DocAccessible.h
@@ -137,6 +137,11 @@ public:
       (mDocumentNode->IsShowing() || HasLoadState(eDOMLoaded));
   }
 
+  bool IsHidden() const
+  {
+    return mDocumentNode->Hidden();
+  }
+
   /**
    * Document load states.
    */