chrome/browser/ui/prefs/pref_watcher.h

// Copyright 2018 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_PREFS_PREF_WATCHER_H_
#define CHROME_BROWSER_UI_PREFS_PREF_WATCHER_H_

#include "base/memory/singleton.h"
#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
#include "components/keyed_service/core/keyed_service.h"
#include "components/prefs/pref_change_registrar.h"
#include "mojo/public/cpp/bindings/remote_set.h"
#include "third_party/blink/public/mojom/renderer_preference_watcher.mojom.h"

class Profile;
class PrefsTabHelper;

// Watches updates in WebKitPreferences and blink::RendererPreferences, and
// notifies tab helpers and registered watchers of those updates.
class PrefWatcher : public KeyedService {
 public:
  explicit PrefWatcher(Profile* profile);
  ~PrefWatcher() override;

  static PrefWatcher* Get(Profile* profile);

  void RegisterHelper(PrefsTabHelper* helper);
  void UnregisterHelper(PrefsTabHelper* helper);
  void RegisterRendererPreferenceWatcher(
      mojo::PendingRemote<blink::mojom::RendererPreferenceWatcher> watcher);

 private:
  // KeyedService overrides:
  void Shutdown() override;

  void UpdateRendererPreferences();
  void OnWebPrefChanged(const std::string& pref_name);
  void OnLiveCaptionEnabledPrefChanged(const std::string& pref_name);

  Profile* profile_;
  PrefChangeRegistrar profile_pref_change_registrar_;
  PrefChangeRegistrar local_state_pref_change_registrar_;

  // |tab_helpers_| observe changes in WebKitPreferences and
  // blink::RendererPreferences.
  std::set<PrefsTabHelper*> tab_helpers_;

  // |renderer_preference_watchers_| observe changes in
  // blink::RendererPreferences. If the consumer also wants to WebKit
  // preference changes, use |tab_helpers_|.
  mojo::RemoteSet<blink::mojom::RendererPreferenceWatcher>
      renderer_preference_watchers_;
};

class PrefWatcherFactory : public BrowserContextKeyedServiceFactory {
 public:
  static PrefWatcher* GetForProfile(Profile* profile);
  static PrefWatcherFactory* GetInstance();

 private:
  friend struct base::DefaultSingletonTraits<PrefWatcherFactory>;

  PrefWatcherFactory();
  ~PrefWatcherFactory() override;

  // BrowserContextKeyedServiceFactory:
  KeyedService* BuildServiceInstanceFor(
      content::BrowserContext* browser_context) const override;

  content::BrowserContext* GetBrowserContextToUse(
      content::BrowserContext* context) const override;
};

#endif  // CHROME_BROWSER_UI_PREFS_PREF_WATCHER_H_