Remove scroll_clip_layer dependency from viewport layer tracking

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 2ebe2a38e146fcc8b73950b4c4743b813d2c9e6a..1d574938134bfda1011247e34ff89a55ea90ef01 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -218,6 +218,8 @@ class CC_EXPORT LayerTreeImpl {
 
   void SetViewportLayersFromIds(int overscroll_elasticity_layer,
                                 int page_scale_layer_id,
+                                int inner_viewport_container_layer_id,
+                                int outer_viewport_container_layer_id,
                                 int inner_viewport_scroll_layer_id,
                                 int outer_viewport_scroll_layer_id);
   void ClearViewportLayers();
@@ -527,6 +529,10 @@ class CC_EXPORT LayerTreeImpl {
   int last_scrolled_scroll_node_index_;
   int overscroll_elasticity_layer_id_;
   int page_scale_layer_id_;
+
+  int inner_viewport_container_layer_id_;
+  int outer_viewport_container_layer_id_;
+
   int inner_viewport_scroll_layer_id_;
   int outer_viewport_scroll_layer_id_;