--- a/gfx/webrender_bindings/src/bindings.rs
+++ b/gfx/webrender_bindings/src/bindings.rs
@@ -1467,16 +1467,17 @@ pub extern "C" fn wr_dp_push_stacking_co
 
     let mut prim_info = LayoutPrimitiveInfo::new(bounds);
     prim_info.is_backface_visible = is_backface_visible;
     prim_info.tag = state.current_tag;
 
     state.frame_builder
          .dl_builder
          .push_stacking_context(&prim_info,
+                                None,
                                 ScrollPolicy::Scrollable,
                                 transform_binding,
                                 transform_style,
                                 perspective,
                                 mix_blend_mode,
                                 filters);
 }
 

--- a/layout/reftests/w3c-css/submitted/masking/reftest.list
+++ b/layout/reftests/w3c-css/submitted/masking/reftest.list
@@ -103,15 +103,15 @@ fuzzy(64,370) == clip-path-strokeBox-1b.
 fuzzy-if(winWidget,1,21) fuzzy-if(skiaContent,1,60) == clip-path-viewBox-1a.html clip-path-geometryBox-1-ref.html
 fuzzy-if(winWidget,1,21) fuzzy-if(skiaContent,1,60) == clip-path-viewBox-1b.html clip-path-geometryBox-1-ref.html
 fuzzy(64,370) == clip-path-viewBox-1c.html clip-path-geometryBox-1-ref.html
 fuzzy-if(winWidget,9,98) fuzzy-if(webrender,64,100) == clip-path-geometryBox-2.html clip-path-geometryBox-2-ref.html
 
 == clip-path-localRef-1.html clip-path-localRef-1-ref.html
 
 # mask with opacity test cases
-fuzzy(1,5000) fails-if(webrender) == mask-opacity-1a.html mask-opacity-1-ref.html
+fuzzy(1,5000) == mask-opacity-1a.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1b.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1c.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1d.html mask-opacity-1-ref.html
 fuzzy(1,5000) == mask-opacity-1e.html mask-opacity-1-ref.html
 
 == clip-path-mix-blend-mode-1.html clip-path-mix-blend-mode-1-ref.html