It is time.

ui/accessibility/ax_tree_source.h

-// Copyright 2013 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_ACCESSIBILITY_AX_TREE_SOURCE_H_
-#define UI_ACCESSIBILITY_AX_TREE_SOURCE_H_
-
-#include <vector>
-
-#include "ui/accessibility/ax_node_data.h"
-
-namespace ui {
-
-// An AXTreeSource is an abstract interface for a serializable
-// accessibility tree. The tree may be in some other format or
-// may be computed dynamically, but maintains the properties that
-// it's a strict tree, it has a unique id for each node, and all
-// of the accessibility information about a node can be serialized
-// as an AXNodeData. This is the primary interface to use when
-// an accessibility tree will be sent over an IPC before being
-// consumed.
-template<typename AXNodeSource>
-class AXTreeSource {
- public:
-  virtual ~AXTreeSource() {}
-
-  // Get the root of the tree.
-  virtual AXNodeSource GetRoot() const = 0;
-
-  // Get a node by its id. If no node by that id exists in the tree, return a
-  // null node, i.e. one that will return false if you call IsValid on it.
-  virtual AXNodeSource GetFromId(int32 id) const = 0;
-
-  // Return the id of a node. All ids must be positive integers.
-  virtual int32 GetId(AXNodeSource node) const = 0;
-
-  // Append all children of |node| to |out_children|.
-  virtual void GetChildren(AXNodeSource node,
-                           std::vector<AXNodeSource>* out_children) const = 0;
-
-  // Get the parent of |node|.
-  virtual AXNodeSource GetParent(AXNodeSource node) const = 0;
-
-  // Returns true if |node| is valid, and false if it's a null pointer or a
-  // node object representing the null pointer.
-  virtual bool IsValid(AXNodeSource node) const = 0;
-
-  // Returns true if two nodes are equal.
-  virtual bool IsEqual(AXNodeSource node1,
-                       AXNodeSource node2) const = 0;
-
-  // Return a AXNodeSource representing null.
-  virtual AXNodeSource GetNull() const = 0;
-
-  // Serialize one node in the tree.
-  virtual void SerializeNode(AXNodeSource node, AXNodeData* out_data) const = 0;
-
- protected:
-  AXTreeSource() {}
-};
-
-}  // namespace ui
-
-#endif  // UI_ACCESSIBILITY_AX_TREE_SOURCE_H_