Factor Google Now welcome notifications out of DesktopNotificationService.

chrome/browser/notifications/extension_welcome_notification_factory.cc

+// 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.
+
+#include "chrome/browser/notifications/extension_welcome_notification_factory.h"
+
+#include "chrome/browser/notifications/desktop_notification_service_factory.h"
+#include "chrome/browser/notifications/extension_welcome_notification.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "content/public/browser/browser_thread.h"
+
+// static
+ExtensionWelcomeNotification*
+ExtensionWelcomeNotificationFactory::GetForBrowserContext(
+    content::BrowserContext* context) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  return static_cast<ExtensionWelcomeNotification*>(
+      GetInstance()->GetServiceForBrowserContext(context, true));
+}
+
+// static
+ExtensionWelcomeNotificationFactory*
+ExtensionWelcomeNotificationFactory::GetInstance() {
+  return Singleton<ExtensionWelcomeNotificationFactory>::get();
+}
+
+ExtensionWelcomeNotificationFactory::ExtensionWelcomeNotificationFactory()
+    : BrowserContextKeyedServiceFactory(
+        "ExtensionWelcomeNotification",
+        BrowserContextDependencyManager::GetInstance()) {
+  DependsOn(DesktopNotificationServiceFactory::GetInstance());
+}
+
+ExtensionWelcomeNotificationFactory::~ExtensionWelcomeNotificationFactory() {}
+
+KeyedService* ExtensionWelcomeNotificationFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  return ExtensionWelcomeNotification::Create(static_cast<Profile*>(context));
+}
+
+content::BrowserContext*
+ExtensionWelcomeNotificationFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextOwnInstanceInIncognito(context);
+}