Rename cc property tree node owner_id to owning_layer_id.

cc/trees/transform_node.h

Index: cc/trees/transform_node.h
diff --git a/cc/trees/transform_node.h b/cc/trees/transform_node.h
index b94bf9ee2ebf7092a37a20d3226d4dfe087f7f21..b98e83cdae96339fe766cdfc12d15c8bfb40b600 100644
--- a/cc/trees/transform_node.h
+++ b/cc/trees/transform_node.h
@@ -22,9 +22,12 @@ struct CC_EXPORT TransformNode {
   TransformNode();
   TransformNode(const TransformNode&);
 
+  // The node index of this node in the transform tree node vector.
   int id;
+  // The node index of the parent node in the transform tree node vector.
   int parent_id;
-  int owner_id;
+  // The layer id of the layer that owns this node.
+  int owning_layer_id;
 
   // The local transform information is combined to form to_parent (ignoring
   // snapping) as follows: