Add the download component and initial setup

chrome/browser/download/background_download_service_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 "chrome/browser/download/background_download_service_factory.h"
+
+#include "base/files/file_path.h"
+#include "base/sequenced_task_runner.h"
+#include "base/task_scheduler/post_task.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/chrome_constants.h"
+#include "components/download/public/background_download_service.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "content/public/browser/browser_context.h"
+
+// static
+BackgroundDownloadServiceFactory*
+BackgroundDownloadServiceFactory::GetInstance() {
+  return base::Singleton<BackgroundDownloadServiceFactory>::get();
+}
+
+// static
+download::BackgroundDownloadService*
+BackgroundDownloadServiceFactory::GetForBrowserContext(
+    content::BrowserContext* context) {
+  return static_cast<download::BackgroundDownloadService*>(
+      GetInstance()->GetServiceForBrowserContext(context, true));
+}
+
+BackgroundDownloadServiceFactory::BackgroundDownloadServiceFactory()
+    : BrowserContextKeyedServiceFactory(
+          "download::BackgroundDownloadService",
+          BrowserContextDependencyManager::GetInstance()) {}
+
+BackgroundDownloadServiceFactory::~BackgroundDownloadServiceFactory() = default;
+
+KeyedService* BackgroundDownloadServiceFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  Profile* profile = Profile::FromBrowserContext(context);
+
+  scoped_refptr<base::SequencedTaskRunner> background_task_runner =
+      base::CreateSequencedTaskRunnerWithTraits(
+          base::TaskTraits().MayBlock().WithPriority(
+              base::TaskPriority::BACKGROUND));
+
+  base::FilePath storage_dir;
+  if (!profile->IsOffTheRecord() && !profile->GetPath().empty()) {
+    storage_dir = profile->GetPath().Append(
+        chrome::kDownloadServicePersistedStorageDirname);
+  }
+
+  download::BackgroundDownloadService* service =
+      download::BackgroundDownloadService::Create(storage_dir,
+                                                  background_task_runner);
+
+  // TODO(dtrainor): Register all clients here.
+  return service;
+}
+
+content::BrowserContext*
+BackgroundDownloadServiceFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextOwnInstanceInIncognito(context);
+}