Backed out changeset a2ddfcc2a7d4 (bug 1618132) for mochitests failures complaining about hittest tests CLOSED TREE

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/6b61e86e08037ba077a5f149fcaad73c6fc1ea42

Author: bogdant-old

webrender/src/render_backend.rs

@@ -581,6 +581,10 @@ impl Document {
                 tile_cache_logger,
             );
 
+            let hit_tester = Arc::new(self.scene.create_hit_tester(&self.data_stores.clip));
+            self.hit_tester = Some(Arc::clone(&hit_tester));
+            self.shared_hit_tester.update(hit_tester);
+
             frame
         };