Use TaskScheduler instead of blocking pool in offline_page_model_factory.cc.

chrome/browser/android/offline_pages/offline_page_model_factory.cc

 // Copyright 2015 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/android/offline_pages/offline_page_model_factory.h"
 
 #include <utility>
 
 #include "base/files/file_path.h"
 #include "base/memory/singleton.h"
 #include "base/sequenced_task_runner.h"
-#include "base/threading/sequenced_worker_pool.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/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/offline_pages/core/offline_page_metadata_store_sql.h"
 #include "components/offline_pages/core/offline_page_model_impl.h"
-#include "content/public/browser/browser_thread.h"
 
 namespace offline_pages {
 
 OfflinePageModelFactory::OfflinePageModelFactory()
     : BrowserContextKeyedServiceFactory(
           "OfflinePageModel",
           BrowserContextDependencyManager::GetInstance()) {
 }
 
 // static
 OfflinePageModelFactory* OfflinePageModelFactory::GetInstance() {
   return base::Singleton<OfflinePageModelFactory>::get();
 }
 
 // static
 OfflinePageModel* OfflinePageModelFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<OfflinePageModelImpl*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 KeyedService* OfflinePageModelFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
-      content::BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
-          content::BrowserThread::GetBlockingPool()->GetSequenceToken());
+      base::CreateSequencedTaskRunnerWithTraits(
+          base::TaskTraits().MayBlock().WithPriority(
+              base::TaskPriority::BACKGROUND));

[dewittj, 2017/04/24 18:44:11]

The tasks on this task runner will sometimes be used to populate UI from a
database, so we were using the blocking pool.  But the comments in TaskPriority
are confusing and suggest that maybe this should be USER_VISIBLE.

[fdoray, 2017/04/26 19:33:06]

Switched to no explicit priority. Priority will be inherited from the calling
context. This is appropriate for code that may be used in different contexts.

 
   base::FilePath store_path =
       profile->GetPath().Append(chrome::kOfflinePageMetadataDirname);
   std::unique_ptr<OfflinePageMetadataStore> metadata_store(
       new OfflinePageMetadataStoreSQL(background_task_runner, store_path));
 
   base::FilePath archives_dir =
       profile->GetPath().Append(chrome::kOfflinePageArchivesDirname);
 
   return new OfflinePageModelImpl(std::move(metadata_store), archives_dir,
                                   background_task_runner);
 }
 
 }  // namespace offline_pages