Remove owning_id from EffectNode and replace it by an opaque stable_id

cc/layers/scrollbar_layer_impl_base.cc

Index: cc/layers/scrollbar_layer_impl_base.cc
diff --git a/cc/layers/scrollbar_layer_impl_base.cc b/cc/layers/scrollbar_layer_impl_base.cc
index 640a26e208d9de6e50587224afa0dfc7964094f4..7ef0f8b88293119cf23d42923a970cc9c32510a9 100644
--- a/cc/layers/scrollbar_layer_impl_base.cc
+++ b/cc/layers/scrollbar_layer_impl_base.cc
@@ -224,16 +224,6 @@ void ScrollbarLayerImplBase::SetOverlayScrollbarLayerOpacityAnimated(
     return;
 
   PropertyTrees* property_trees = layer_tree_impl()->property_trees();
-  int effect_node_index =
-      property_trees->effect_tree.FindNodeIndexFromOwningLayerId(id());
-  // If this method is called during LayerImpl::PushPropertiesTo, we may not yet
-  // have valid owning_layer_id_to_node_index entries in effect tree as property
-  // trees are pushed after layers during activation. We can skip updating
-  // opacity in that case as we are only registering a scrollbar and because
-  // opacity will be overwritten anyway when property trees are pushed.
-  if (effect_node_index == EffectTree::kInvalidNodeId ||
-      effect_node_index != effect_tree_index())
-    return;
 
   EffectNode* node = property_trees->effect_tree.Node(effect_tree_index());
   if (node->opacity == opacity)