chrome/browser/ui/ash/tablet_mode_client.h

// Copyright 2017 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 CHROME_BROWSER_UI_ASH_TABLET_MODE_CLIENT_H_
#define CHROME_BROWSER_UI_ASH_TABLET_MODE_CLIENT_H_

#include "ash/public/interfaces/tablet_mode.mojom.h"
#include "base/macros.h"
#include "base/observer_list.h"
#include "mojo/public/cpp/bindings/binding.h"

class TabletModeClientObserver;

// Holds tablet mode state in chrome. Observes ash for changes, then
// synchronously fires all its observers. This allows all tablet mode code in
// chrome to see a state change at the same time.
class TabletModeClient : public ash::mojom::TabletModeClient {
 public:
  TabletModeClient();
  ~TabletModeClient() override;

  // Initializes and connects to ash.
  void Init();

  // Tests can provide a mock mojo interface for the ash controller.
  void InitForTesting(ash::mojom::TabletModeControllerPtr controller);

  static TabletModeClient* Get();

  bool tablet_mode_enabled() const { return tablet_mode_enabled_; }
  bool auto_hide_title_bars() const { return auto_hide_title_bars_; }

  // Adds the observer and immediately triggers it with the initial state.
  void AddObserver(TabletModeClientObserver* observer);

  void RemoveObserver(TabletModeClientObserver* observer);

  // ash::mojom::TabletModeClient:
  void OnTabletModeToggled(bool enabled) override;

  // Flushes the mojo pipe to ash.
  void FlushForTesting();

 private:
  // Binds this object to its mojo interface and sets it as the ash client.
  void BindAndSetClient();

  bool tablet_mode_enabled_ = false;

  // Whether title bars should be shown be auto hidden in tablet mode.
  const bool auto_hide_title_bars_;

  // Binds to the client interface in ash.
  mojo::Binding<ash::mojom::TabletModeClient> binding_;

  // Keeps the interface pipe alive to receive mojo return values.
  ash::mojom::TabletModeControllerPtr tablet_mode_controller_;

  base::ObserverList<TabletModeClientObserver, true /* check_empty */>
      observers_;

  DISALLOW_COPY_AND_ASSIGN(TabletModeClient);
};

#endif  // CHROME_BROWSER_UI_ASH_TABLET_MODE_CLIENT_H_