Rename cc property tree node owner_id to owning_layer_id.

cc/trees/effect_node.h

Index: cc/trees/effect_node.h
diff --git a/cc/trees/effect_node.h b/cc/trees/effect_node.h
index eab77287cdd79c20b82065e886654e7805ebf4eb..0d04ddc414949503e77378e69608c09b1281962b 100644
--- a/cc/trees/effect_node.h
+++ b/cc/trees/effect_node.h
@@ -25,9 +25,12 @@ struct CC_EXPORT EffectNode {
   EffectNode();
   EffectNode(const EffectNode& other);
 
+  // The node index of this node in the effect tree node vector.
   int id;
+  // The node index of the parent node in the effect tree node vector.
   int parent_id;
-  int owner_id;
+  // The layer id of the layer that owns this node.
+  int owning_layer_id;
 
   float opacity;
   float screen_space_opacity;