Bug 1461342 - Update for API change in WR PR 2762. r=jrmuizel

MozReview-Commit-ID: 3MHCV00262v

--HG--
extra : rebase_source : 2e504a215eb5edd69e30bea3539ac11239d490de

gfx/webrender_bindings/src/bindings.rs

@@ -1869,7 +1869,7 @@ pub extern "C" fn wr_dp_push_iframe(state: &mut WrState,
     let mut prim_info = LayoutPrimitiveInfo::new(rect);
     prim_info.is_backface_visible = is_backface_visible;
     prim_info.tag = state.current_tag;
-    state.frame_builder.dl_builder.push_iframe(&prim_info, pipeline_id);
+    state.frame_builder.dl_builder.push_iframe(&prim_info, pipeline_id, true);
 }
 
 #[no_mangle]