Implement pin storage backend.

chrome/browser/chromeos/login/quick_unlock/pin_storage_factory.h

+// Copyright 2016 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_CHROMEOS_LOGIN_QUICK_UNLOCK_PIN_STORAGE_FACTORY_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_QUICK_UNLOCK_PIN_STORAGE_FACTORY_H_
+
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+class Profile;
+
+namespace chromeos {
+
+class PinStorage;
+
+// Singleton that owns all PinStorage instances and associates them with
+// Profiles. Listens for the Profile's destruction notification and cleans up
+// the associated PinStorage.
+class PinStorageFactory : public BrowserContextKeyedServiceFactory {
+ public:
+  // Returns the PinStorage instance for |profile|.
+  static PinStorage* GetForProfile(Profile* profile);
+
+  static PinStorageFactory* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<PinStorageFactory>;
+
+  PinStorageFactory();
+  ~PinStorageFactory() override;
+
+  // BrowserContextKeyedServiceFactory:
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* profile) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(PinStorageFactory);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_QUICK_UNLOCK_PIN_STORAGE_FACTORY_H_