It is time.

ui/compositor/layer_tree_owner.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef UI_COMPOSITOR_LAYER_TREE_OWNER_H_
-#define UI_COMPOSITOR_LAYER_TREE_OWNER_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "ui/compositor/compositor_export.h"
-
-namespace ui {
-
-class Layer;
-
-// Scoping object that owns a Layer and all its descendants.
-class COMPOSITOR_EXPORT LayerTreeOwner {
- public:
-  explicit LayerTreeOwner(Layer* root);
-  ~LayerTreeOwner();
-
-  Layer* release() WARN_UNUSED_RESULT {
-    Layer* root = root_;
-    root_ = NULL;
-    return root;
-  }
-
-  Layer* root() { return root_; }
-  const Layer* root() const { return root_; }
-
- private:
-  Layer* root_;
-
-  DISALLOW_COPY_AND_ASSIGN(LayerTreeOwner);
-};
-
-}  // namespace
-
-#endif  // UI_COMPOSITOR_LAYER_TREE_OWNER_H_