Remove owning_id from EffectNode and replace it by an opaque stable_id

cc/trees/property_tree_builder.cc

Index: cc/trees/property_tree_builder.cc
diff --git a/cc/trees/property_tree_builder.cc b/cc/trees/property_tree_builder.cc
index 3a3e1dbaf8682a54815be47e65b07eb614f65381..e290e2af12ceb4a1d1ddb07014d352d3ab6b1fdc 100644
--- a/cc/trees/property_tree_builder.cc
+++ b/cc/trees/property_tree_builder.cc
@@ -917,10 +917,11 @@ bool AddEffectNodeIfNeeded(
   int node_id = effect_tree.Insert(EffectNode(), parent_id);
   EffectNode* node = effect_tree.back();
 
-  node->owning_layer_id = layer->id();
+  node->stable_id = layer->id();
   if (AlwaysUseActiveTreeOpacity(layer)) {
+    DCHECK(layer->element_id());
     data_for_children->property_trees->always_use_active_tree_opacity_effect_ids
-        .push_back(node->owning_layer_id);
+        .push_back(layer->element_id());
   }
 
   node->opacity = Opacity(layer);
@@ -974,8 +975,6 @@ bool AddEffectNodeIfNeeded(
       node->closest_ancestor_with_copy_request_id;
   data_for_children->effect_tree_parent = node_id;
   layer->SetEffectTreeIndex(node_id);
-  data_for_children->property_trees->effect_tree.SetOwningLayerIdForNode(
-      effect_tree.back(), layer->id());
 
   // For animation subsystem purposes, if this layer has a compositor element
   // id, we build a map from that id to this effect node.