ash/drag_drop/tab_drag_drop_windows_hider.h

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef ASH_DRAG_DROP_TAB_DRAG_DROP_WINDOWS_HIDER_H_
#define ASH_DRAG_DROP_TAB_DRAG_DROP_WINDOWS_HIDER_H_

#include <map>

#include "ash/ash_export.h"
#include "base/memory/raw_ptr.h"
#include "ui/aura/window.h"
#include "ui/aura/window_observer.h"

namespace ash {

// Hides all visible windows except the source window from which the webui tab
// drag originates, and restores the windows' visibility upon its destruction.
// It also blurs and darkens the background, hides the home launcher if home
// launcher is enabled. Only need to do so if we need to scale up and down the
// source window when dragging a web ui tab out of it.
class ASH_EXPORT TabDragDropWindowsHider : public aura::WindowObserver {
 public:
  explicit TabDragDropWindowsHider(aura::Window* source_window);

  TabDragDropWindowsHider(const TabDragDropWindowsHider&) = delete;
  TabDragDropWindowsHider& operator=(const TabDragDropWindowsHider&) = delete;

  ~TabDragDropWindowsHider() override;

  // aura::WindowObserver:
  void OnWindowDestroying(aura::Window* window) override;
  void OnWindowVisibilityChanged(aura::Window* window, bool visible) override;

  int GetWindowVisibilityMapSizeForTesting() const;

 private:
  // The window from which the drag originated.
  raw_ptr<aura::Window> source_window_;

  // The root window the drag is taking place within. Guaranteed to be
  // non-null during the lifetime of |this|.
  raw_ptr<aura::Window> root_window_;

  // Maintains the map between windows and their visibilities. All windows
  // except the dragged window and the source window should stay hidden during
  // dragging.
  std::map<aura::Window*, bool> window_visibility_map_;
};

}  // namespace ash

#endif  // ASH_DRAG_DROP_TAB_DRAG_DROP_WINDOWS_HIDER_H_