Introduce a layering in the invalidation component as public and impl

components/invalidation/invalidator_storage.h

-// Copyright 2014 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 COMPONENTS_INVALIDATION_INVALIDATOR_STORAGE_H_
-#define COMPONENTS_INVALIDATION_INVALIDATOR_STORAGE_H_
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/threading/thread_checker.h"
-#include "components/invalidation/invalidation_state_tracker.h"
-
-class PrefRegistrySimple;
-class PrefService;
-
-namespace user_prefs {
-class PrefRegistrySyncable;
-}
-
-namespace invalidation {
-
-// Wraps PrefService in an InvalidationStateTracker to allow SyncNotifiers
-// to use PrefService as persistence for invalidation state. It is not thread
-// safe, and lives on the UI thread.
-class InvalidatorStorage : public syncer::InvalidationStateTracker {
- public:
-  // |pref_service| may not be NULL and must outlive |this|.
-  explicit InvalidatorStorage(PrefService* pref_service);
-  ~InvalidatorStorage() override;
-
-  // Register prefs to be used by per-Profile instances of this class which
-  // store invalidation state in Profile prefs.
-  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
-
-  // Register prefs to be used by a device-global instance of this class which
-  // stores invalidation state in local state. This is used on Chrome OS only.
-  static void RegisterPrefs(PrefRegistrySimple* registry);
-
-  // InvalidationStateTracker implementation.
-  void ClearAndSetNewClientId(const std::string& client_id) override;
-  std::string GetInvalidatorClientId() const override;
-  void SetBootstrapData(const std::string& data) override;
-  std::string GetBootstrapData() const override;
-  void SetSavedInvalidations(
-      const syncer::UnackedInvalidationsMap& map) override;
-  syncer::UnackedInvalidationsMap GetSavedInvalidations() const override;
-  void Clear() override;
-
- private:
-  base::ThreadChecker thread_checker_;
-
-  PrefService* const pref_service_;
-
-  DISALLOW_COPY_AND_ASSIGN(InvalidatorStorage);
-};
-
-}  // namespace invalidation
-
-#endif  // COMPONENTS_INVALIDATION_INVALIDATOR_STORAGE_H_