cc : Remove parent for mask and replica layers in LayerImpl

cc/trees/occlusion_tracker_unittest.cc

Index: cc/trees/occlusion_tracker_unittest.cc
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index 5aa72c39f300f704acc2d4b13896f92699205057..e32134e69e9f5afd946afa22d8a6265257cd9621 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -298,6 +298,8 @@ class OcclusionTrackerTest : public testing::Test {
   }
 
   void SetReplica(LayerImpl* owning_layer, scoped_ptr<LayerImpl> layer) {
+    // We need to set parent on replica layer for property tree building.
+    layer->SetParent(owning_layer);
     owning_layer->SetReplicaLayer(std::move(layer));
   }