Add a mojo bridge for PersistentPrefStore.

services/preferences/public/cpp/persistent_pref_store_mojo.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 SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_MOJO_H_
+#define SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_MOJO_H_
+
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "base/single_thread_task_runner.h"
+#include "base/values.h"
+#include "components/prefs/persistent_pref_store.h"
+#include "services/preferences/public/interfaces/preferences.mojom.h"
+
+namespace prefs {
+
+// An implementation of PersistentPrefStore which uses
+// mojom::PersistentPrefStore as the backing of the preferences.
+//
+// TODO(sammc): Make this an implementation detail once the PrefService
+// factory/builder is responsible for constructing the user prefs PrefStore.
+class PersistentPrefStoreMojo : public PersistentPrefStore {
+ public:
+  explicit PersistentPrefStoreMojo(
+      mojom::PersistentPrefStoreConnectorPtr connector);
+
+  // PrefStore:
+  bool GetValue(const std::string& key,
+                const base::Value** value) const override;
+  std::unique_ptr<base::DictionaryValue> GetValues() const override;
+  void AddObserver(PrefStore::Observer* observer) override;
+  void RemoveObserver(PrefStore::Observer* observer) override;
+  bool HasObservers() const override;
+  bool IsInitializationComplete() const override;
+
+  // WriteablePrefStore overrides.
+  void SetValue(const std::string& key,
+                std::unique_ptr<base::Value> value,
+                uint32_t flags) override;
+  void RemoveValue(const std::string& key, uint32_t flags) override;
+  bool GetMutableValue(const std::string& key, base::Value** result) override;
+  void ReportValueChanged(const std::string& key, uint32_t flags) override;
+  void SetValueSilently(const std::string& key,
+                        std::unique_ptr<base::Value> value,
+                        uint32_t flags) override;
+
+  // PersistentPrefStore overrides.
+  bool ReadOnly() const override;
+  PrefReadError GetReadError() const override;
+  PrefReadError ReadPrefs() override;
+  void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
+  void CommitPendingWrite() override;
+  void SchedulePendingLossyWrites() override;
+  void ClearMutableValues() override;
+
+ protected:
+  // base::RefCounted<PrefStore>:
+  ~PersistentPrefStoreMojo() override;
+
+ private:
+  void OnCreateComplete(PrefReadError read_error,
+                        bool read_only,
+                        std::unique_ptr<base::DictionaryValue> local_prefs,
+                        mojom::PersistentPrefStorePtr pref_store);
+
+  mojom::PersistentPrefStoreConnectorPtr connector_;
+  bool read_only_ = false;
+  PrefReadError read_error_ = PersistentPrefStore::PREF_READ_ERROR_NONE;
+  mojom::PersistentPrefStorePtr pref_store_;
+  mojom::PersistentPrefStoreRequest pref_store_request_;
+
+  std::unique_ptr<base::DictionaryValue> local_prefs_;
+
+  std::unique_ptr<ReadErrorDelegate> error_delegate_;
+  base::ObserverList<PrefStore::Observer, true> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(PersistentPrefStoreMojo);
+};
+
+}  // namespace prefs
+
+#endif  // SERVICES_PREFERENCES_PUBLIC_CPP_PERSISTENT_PREF_STORE_MOJO_H_