[extension SW] Support lazy events from extension service workers.

extensions/browser/service_worker_task_queue_factory.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 "extensions/browser/service_worker_task_queue_factory.h"
+
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "extensions/browser/extensions_browser_client.h"
+#include "extensions/browser/service_worker_task_queue.h"
+
+using content::BrowserContext;
+namespace extensions {
+
+// static
+ServiceWorkerTaskQueue* ServiceWorkerTaskQueueFactory::GetForBrowserContext(
+    BrowserContext* context) {
+  return static_cast<ServiceWorkerTaskQueue*>(
+      GetInstance()->GetServiceForBrowserContext(context, true));
+}
+
+// static
+ServiceWorkerTaskQueueFactory* ServiceWorkerTaskQueueFactory::GetInstance() {
+  return base::Singleton<ServiceWorkerTaskQueueFactory>::get();
+}
+
+ServiceWorkerTaskQueueFactory::ServiceWorkerTaskQueueFactory()
+    : BrowserContextKeyedServiceFactory(
+          "ServiceWorkerTaskQueue",
+          BrowserContextDependencyManager::GetInstance()) {}
+
+ServiceWorkerTaskQueueFactory::~ServiceWorkerTaskQueueFactory() {}
+
+KeyedService* ServiceWorkerTaskQueueFactory::BuildServiceInstanceFor(
+    BrowserContext* context) const {
+  return new ServiceWorkerTaskQueue(context);
+}
+
+BrowserContext* ServiceWorkerTaskQueueFactory::GetBrowserContextToUse(
+    BrowserContext* context) const {
+  // Redirected in incognito.
+  return ExtensionsBrowserClient::Get()->GetOriginalContext(context);
+}
+
+}  // namespace extensions