Use TaskScheduler instead of blocking pool in supervised_user_blacklist.cc.

chrome/browser/supervised_user/experimental/supervised_user_blacklist.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/supervised_user/experimental/supervised_user_blacklist.h"
 
 #include <algorithm>
 #include <cstring>
 #include <fstream>
 
 #include "base/files/file_path.h"
 #include "base/files/memory_mapped_file.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "content/public/browser/browser_thread.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
 
 namespace {
 
 std::unique_ptr<std::vector<SupervisedUserBlacklist::Hash>>
 ReadFromBinaryFileOnFileThread(const base::FilePath& path) {
-  DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
-
   std::unique_ptr<std::vector<SupervisedUserBlacklist::Hash>> host_hashes(
       new std::vector<SupervisedUserBlacklist::Hash>);
 
   base::MemoryMappedFile file;
   file.Initialize(path);
   if (!file.IsValid())
     return host_hashes;
 
   size_t size = file.length();
   if (size <= 0 || size % base::kSHA1Length != 0)
@@ skipping 33 matching lines @@
   Hash hash(url.host());
   return std::binary_search(host_hashes_.begin(), host_hashes_.end(), hash);
 }
 
 size_t SupervisedUserBlacklist::GetEntryCount() const {
   return host_hashes_.size();
 }
 
 void SupervisedUserBlacklist::ReadFromFile(const base::FilePath& path,
                                            const base::Closure& done_callback) {
   base::PostTaskAndReplyWithResult(

[Bernhard Bauer, 2017/04/27 09:13:38]

Sorry, I thought I had replied here as well. Can you use
PostTaskWithTraitsAndReplyWithResult() here? And maybe replace base::Bind() with
base::BindOnce()? Thanks!

-      BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
-          base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN).get(),
-      FROM_HERE,
-      base::Bind(&ReadFromBinaryFileOnFileThread, path),
+      base::CreateTaskRunnerWithTraits(
+          base::TaskTraits()
+              .MayBlock()
+              .WithPriority(base::TaskPriority::BACKGROUND)
+              .WithShutdownBehavior(
+                  base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN))
+          .get(),
+      FROM_HERE, base::Bind(&ReadFromBinaryFileOnFileThread, path),
       base::Bind(&SupervisedUserBlacklist::OnReadFromFileCompleted,
-                 weak_ptr_factory_.GetWeakPtr(),
-                 done_callback));
+                 weak_ptr_factory_.GetWeakPtr(), done_callback));
 }
 
 void SupervisedUserBlacklist::OnReadFromFileCompleted(
     const base::Closure& done_callback,
     std::unique_ptr<std::vector<Hash>> host_hashes) {
   host_hashes_.swap(*host_hashes);
   LOG_IF(WARNING, host_hashes_.empty()) << "Got empty blacklist";
 
   if (!done_callback.is_null())
     done_callback.Run();
 }