1 files changed, 15 insertions, 22 deletions

diff --git a/components/layout/display_list/webrender_helpers.rs b/components/layout/display_list/webrender_helpers.rs
index 1e584c0c06f..a8130a15936 100644
--- a/components/layout/display_list/webrender_helpers.rs
+++ b/components/layout/display_list/webrender_helpers.rs
@@ -49,7 +49,6 @@ impl<'a> ClipScrollState<'a> {
 
         let root_clip_chain =
             builder.define_clip_chain(None, [ClipId::root(state.compositor_info.pipeline_id)]);
-
         state.add_clip_node_mapping(0, root_clip_chain);
         state.add_clip_node_mapping(1, root_clip_chain);
 
@@ -115,7 +114,11 @@ impl DisplayList {
         epoch: Epoch,
     ) -> (DisplayListBuilder, CompositorDisplayListInfo, IsContentful) {
         let webrender_pipeline = pipeline_id.to_webrender();
-        let mut builder = DisplayListBuilder::new(webrender_pipeline);
+        let mut builder = DisplayListBuilder::with_capacity(
+            webrender_pipeline,
+            self.bounds().size,
+            1024 * 1024, // 1 MB of space
+        );
 
         let content_size = self.bounds().size;
         let mut state = ClipScrollState::new(
@@ -153,16 +156,17 @@ impl DisplayItem {
         let internal_clip_id = clip_and_scroll_indices
             .clipping
             .unwrap_or(clip_and_scroll_indices.scrolling);
-        let current_clip_chain_id = state.webrender_clip_id_for_index(internal_clip_id.to_index());
+        let current_clip_id = state.webrender_clip_id_for_index(internal_clip_id.to_index());
         let hit_test_bounds = self.bounds().intersection(&self.base().clip_rect);
 
         let build_common_item_properties = |base: &BaseDisplayItem| {
             CommonItemProperties {
                 clip_rect: base.clip_rect,
                 spatial_id: current_scroll_node_id.spatial_id,
-                clip_id: ClipId::ClipChain(current_clip_chain_id),
+                clip_id: ClipId::ClipChain(current_clip_id),
                 // TODO(gw): Make use of the WR backface visibility functionality.
                 flags: PrimitiveFlags::default(),
+                hit_info: None,
             }
         };
 
@@ -183,15 +187,10 @@ impl DisplayItem {
                 current_scroll_node_id,
             );
 
-            builder.push_hit_test(
-                &CommonItemProperties {
-                    clip_rect: bounds,
-                    spatial_id: current_scroll_node_id.spatial_id,
-                    clip_id: ClipId::ClipChain(current_clip_chain_id),
-                    flags: PrimitiveFlags::default(),
-                },
-                (hit_test_index as u64, 0u16),
-            );
+            let mut common = build_common_item_properties(base);
+            common.hit_info = Some((hit_test_index as u64, 0u16));
+            common.clip_rect = bounds;
+            builder.push_hit_test(&common);
         };
 
         match *self {
@@ -303,13 +302,7 @@ impl DisplayItem {
                                         scrolling_relative_to: None,
                                     },
                                 ),
-                                (Some(t), None) => (
-                                    t,
-                                    ReferenceFrameKind::Transform {
-                                        is_2d_scale_translation: false,
-                                        should_snap: false,
-                                    },
-                                ),
+                                (Some(t), None) => (t, ReferenceFrameKind::Transform),
                                 (Some(t), Some(p)) => (
                                     p.then(&t),
                                     ReferenceFrameKind::Perspective {
@@ -328,7 +321,7 @@ impl DisplayItem {
                         );
 
                         let index = frame_index.to_index();
-                        state.add_clip_node_mapping(index, current_clip_chain_id);
+                        state.add_clip_node_mapping(index, current_clip_id);
                         state.register_spatial_node(
                             index,
                             new_spatial_id,
@@ -415,7 +408,7 @@ impl DisplayItem {
                         let spatial_id = builder
                             .define_scroll_frame(
                                 &parent_space_and_clip_info,
-                                external_id,
+                                Some(external_id),
                                 node.content_rect,
                                 item_rect,
                                 scroll_sensitivity,