ui/accessibility/ax_tree_source_observer.h

// Copyright 2021 The Chromium Authors
// 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_OBSERVER_H_
#define UI_ACCESSIBILITY_AX_TREE_SOURCE_OBSERVER_H_

#include "base/observer_list_types.h"
#include "ui/accessibility/ax_export.h"

namespace ui {

template <typename AXNodeSource>
class AXTreeSource;

// This is an interface for a class that observes changes to an `AXTreeSource`.
template <typename AXNodeSource>
class AX_EXPORT AXTreeSourceObserver : public base::CheckedObserver {
 public:
  ~AXTreeSourceObserver() override = default;

  virtual void OnNodeAdded(const AXTreeSource<AXNodeSource>& tree_source,
                           const AXNodeSource& node_source) = 0;
  virtual void OnNodeUpdated(const AXTreeSource<AXNodeSource>& tree_source,
                             const AXNodeSource& node_source) = 0;
  virtual void OnNodeRemoved(const AXTreeSource<AXNodeSource>& tree_source,
                             const AXNodeSource& node_source) = 0;
};

}  // namespace ui

#endif  // UI_ACCESSIBILITY_AX_TREE_SOURCE_OBSERVER_H_