[EasyUnlock] Introduce EasyUnlockNotificationController

chrome/browser/signin/easy_unlock_notification_controller.cc

+// 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.
+
+#include "chrome/browser/signin/easy_unlock_notification_controller.h"
+
+#include "base/memory/ptr_util.h"
+
+#if defined(OS_CHROMEOS)
+#include "chrome/browser/signin/easy_unlock_notification_controller_chromeos.h"
+#include "ui/message_center/message_center.h"
+#endif
+
+namespace {
+
+// Stub implementation of EasyUnlockNotificationController for non-ChromeOS
+// platforms.
+class EasyUnlockNotificationControllerStub
+    : public EasyUnlockNotificationController {
+ public:
+  EasyUnlockNotificationControllerStub() {}
+  ~EasyUnlockNotificationControllerStub() override {}
+
+  // EasyUnlockNotificationController:
+  void ShowChromebookAddedNotification() override {}
+  void ShowPairingChangeNotification() override {}
+  void ShowPairingChangeAppliedNotification(
+      const std::string& phone_name) override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EasyUnlockNotificationControllerStub);
+};
+
+}  // namespace
+
+std::unique_ptr<EasyUnlockNotificationController>
+EasyUnlockNotificationController::Create(Profile* profile) {
+#if defined(OS_CHROMEOS)
+  return base::MakeUnique<EasyUnlockNotificationControllerChromeOS>(
+      profile, message_center::MessageCenter::Get());

[Peter Beverloo, 2017/07/07 18:36:58]

Will this functionality stay restricted to Chrome OS? Note that you cannot rely
on there being a message center on the other platforms.

[Tim Song, 2017/07/07 19:54:04]

Yes. At the moment these notifications are only intended for ChromeOS. 

+#else
+  return base::MakeUnique<EasyUnlockNotificationControllerStub>();
+#endif
+}