From 7d672555be73bf0a057e8596b96d3843b0627eb2 Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Fri, 22 Jun 2018 17:56:11 +0200
Subject: [PATCH] Give stacking contexts the right reference frame id

Stacking contexts that create reference frames should be created with
the positioning node set to the reference frames that surround them.
---
 components/layout/display_list/webrender_helpers.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/components/layout/display_list/webrender_helpers.rs b/components/layout/display_list/webrender_helpers.rs
index a6070ecb61d..d056d8c4655 100644
--- a/components/layout/display_list/webrender_helpers.rs
+++ b/components/layout/display_list/webrender_helpers.rs
@@ -235,6 +235,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
 
                     info.rect.origin = LayoutPoint::zero();
                     info.clip_rect.origin = LayoutPoint::zero();
+                    builder.push_clip_id(clip_id);
                 }
 
                 builder.push_stacking_context(
@@ -245,6 +246,10 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                     stacking_context.filters.clone(),
                     GlyphRasterSpace::Screen,
                 );
+
+                if stacking_context.established_reference_frame.is_some() {
+                    builder.pop_clip_id();
+                }
             },
             DisplayItem::PopStackingContext(_) => builder.pop_stacking_context(),
             DisplayItem::DefineClipScrollNode(ref item) => {