From 01c0e2aba0ccf032cc9ff2788b9874af354418ae Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Wed, 30 May 2018 18:17:02 +0200
Subject: [PATCH] Changes for separate reference frame PR (#2756)

---
 .../layout/display_list/webrender_helpers.rs  | 32 ++++++++++++-------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/components/layout/display_list/webrender_helpers.rs b/components/layout/display_list/webrender_helpers.rs
index 2e805f35a41f..a6070ecb61d8 100644
--- a/components/layout/display_list/webrender_helpers.rs
+++ b/components/layout/display_list/webrender_helpers.rs
@@ -11,6 +11,7 @@ use display_list::items::{BorderDetails, ClipScrollNode, ClipScrollNodeIndex, Cl
 use display_list::items::{DisplayItem, DisplayList, StackingContextType};
 use msg::constellation_msg::PipelineId;
 use webrender_api::{self, ClipAndScrollInfo, ClipId, DisplayListBuilder, GlyphRasterSpace};
+use webrender_api::LayoutPoint;
 
 pub trait WebRenderDisplayListConverter {
     fn convert_to_webrender(&self, pipeline_id: PipelineId) -> DisplayListBuilder;
@@ -218,23 +219,32 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                 let stacking_context = &item.stacking_context;
                 debug_assert_eq!(stacking_context.context_type, StackingContextType::Real);
 
-                let reference_frame_clip_id = builder.push_stacking_context(
-                    &webrender_api::LayoutPrimitiveInfo::new(stacking_context.bounds),
+                let mut info = webrender_api::LayoutPrimitiveInfo::new(stacking_context.bounds);
+                if let Some(frame_index) = stacking_context.established_reference_frame {
+                    debug_assert!(
+                        stacking_context.transform.is_some() ||
+                        stacking_context.perspective.is_some()
+                    );
+
+                    let clip_id = builder.push_reference_frame(
+                        &info.clone(),
+                        stacking_context.transform.map(Into::into),
+                        stacking_context.perspective,
+                    );
+                    clip_ids[frame_index.to_index()] = Some(clip_id);
+
+                    info.rect.origin = LayoutPoint::zero();
+                    info.clip_rect.origin = LayoutPoint::zero();
+                }
+
+                builder.push_stacking_context(
+                    &info,
                     None,
-                    stacking_context.transform.map(Into::into),
                     stacking_context.transform_style,
-                    stacking_context.perspective,
                     stacking_context.mix_blend_mode,
                     stacking_context.filters.clone(),
                     GlyphRasterSpace::Screen,
                 );
-
-                match (reference_frame_clip_id, stacking_context.established_reference_frame) {
-                    (Some(webrender_id), Some(frame_index)) =>
-                        clip_ids[frame_index.to_index()] = Some(webrender_id),
-                    (None, None) => {},
-                    _ => warn!("Mismatch between reference frame establishment!"),
-                }
             },
             DisplayItem::PopStackingContext(_) => builder.pop_stacking_context(),
             DisplayItem::DefineClipScrollNode(ref item) => {