Revert of Move base/prefs to components/prefs

components/prefs/pref_notifier_impl.h

-// Copyright (c) 2011 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 BASE_PREFS_PREF_NOTIFIER_IMPL_H_
-#define BASE_PREFS_PREF_NOTIFIER_IMPL_H_
-
-#include <list>
-#include <string>
-
-#include "base/callback.h"
-#include "base/compiler_specific.h"
-#include "base/containers/hash_tables.h"
-#include "base/macros.h"
-#include "base/observer_list.h"
-#include "base/prefs/base_prefs_export.h"
-#include "base/prefs/pref_notifier.h"
-#include "base/prefs/pref_observer.h"
-#include "base/threading/thread_checker.h"
-
-class PrefService;
-
-// The PrefNotifier implementation used by the PrefService.
-class BASE_PREFS_EXPORT PrefNotifierImpl
-    : public NON_EXPORTED_BASE(PrefNotifier) {
- public:
-  PrefNotifierImpl();
-  explicit PrefNotifierImpl(PrefService* pref_service);
-  ~PrefNotifierImpl() override;
-
-  // If the pref at the given path changes, we call the observer's
-  // OnPreferenceChanged method.
-  void AddPrefObserver(const std::string& path, PrefObserver* observer);
-  void RemovePrefObserver(const std::string& path, PrefObserver* observer);
-
-  // We run the callback once, when initialization completes. The bool
-  // parameter will be set to true for successful initialization,
-  // false for unsuccessful.
-  void AddInitObserver(base::Callback<void(bool)> observer);
-
-  void SetPrefService(PrefService* pref_service);
-
- protected:
-  // PrefNotifier overrides.
-  void OnPreferenceChanged(const std::string& pref_name) override;
-  void OnInitializationCompleted(bool succeeded) override;
-
-  // A map from pref names to a list of observers. Observers get fired in the
-  // order they are added. These should only be accessed externally for unit
-  // testing.
-  typedef base::ObserverList<PrefObserver> PrefObserverList;
-  typedef base::hash_map<std::string, PrefObserverList*> PrefObserverMap;
-
-  typedef std::list<base::Callback<void(bool)>> PrefInitObserverList;
-
-  const PrefObserverMap* pref_observers() const { return &pref_observers_; }
-
- private:
-  // For the given pref_name, fire any observer of the pref. Virtual so it can
-  // be mocked for unit testing.
-  virtual void FireObservers(const std::string& path);
-
-  // Weak reference; the notifier is owned by the PrefService.
-  PrefService* pref_service_;
-
-  PrefObserverMap pref_observers_;
-  PrefInitObserverList init_observers_;
-
-  base::ThreadChecker thread_checker_;
-
-  DISALLOW_COPY_AND_ASSIGN(PrefNotifierImpl);
-};
-
-#endif  // BASE_PREFS_PREF_NOTIFIER_IMPL_H_