Use SequencedTaskRunner rather than SingledThreadedTaskRunner for passing io_task_runner

net/proxy/proxy_config_service_mac.cc

 // Copyright (c) 2012 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 "net/proxy/proxy_config_service_mac.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <SystemConfiguration/SystemConfiguration.h>
 
 #include "base/bind.h"
@@ skipping 180 matching lines @@
     SCDynamicStoreRef store) {
   proxy_config_service_->SetDynamicStoreNotificationKeys(store);
 }
 
 void ProxyConfigServiceMac::Forwarder::OnNetworkConfigChange(
     CFArrayRef changed_keys) {
   proxy_config_service_->OnNetworkConfigChange(changed_keys);
 }
 
 ProxyConfigServiceMac::ProxyConfigServiceMac(
-    const scoped_refptr<base::SingleThreadTaskRunner>& io_thread_task_runner)
+    const scoped_refptr<base::SequencedTaskRunner>& io_thread_task_runner)
     : forwarder_(this),
       has_fetched_config_(false),
       helper_(new Helper(this)),
       io_thread_task_runner_(io_thread_task_runner) {
   DCHECK(io_thread_task_runner_.get());
   config_watcher_.reset(new NetworkConfigWatcherMac(&forwarder_));
 }
 
 ProxyConfigServiceMac::~ProxyConfigServiceMac() {
-  DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
+  DCHECK(io_thread_task_runner_->RunsTasksInCurrentSequence());
   // Delete the config_watcher_ to ensure the notifier thread finishes before
   // this object is destroyed.
   config_watcher_.reset();
   helper_->Orphan();
 }
 
 void ProxyConfigServiceMac::AddObserver(Observer* observer) {
-  DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
+  DCHECK(io_thread_task_runner_->RunsTasksInCurrentSequence());
   observers_.AddObserver(observer);
 }
 
 void ProxyConfigServiceMac::RemoveObserver(Observer* observer) {
-  DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
+  DCHECK(io_thread_task_runner_->RunsTasksInCurrentSequence());
   observers_.RemoveObserver(observer);
 }
 
 ProxyConfigService::ConfigAvailability
 ProxyConfigServiceMac::GetLatestProxyConfig(ProxyConfig* config) {
-  DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
+  DCHECK(io_thread_task_runner_->RunsTasksInCurrentSequence());
 
   // Lazy-initialize by fetching the proxy setting from this thread.
   if (!has_fetched_config_) {
     GetCurrentProxyConfig(&last_config_fetched_);
     has_fetched_config_ = true;
   }
 
   *config = last_config_fetched_;
   return has_fetched_config_ ? CONFIG_VALID : CONFIG_PENDING;
 }
@@ skipping 22 matching lines @@
   GetCurrentProxyConfig(&new_config);
 
   // Call OnProxyConfigChanged() on the IO thread to notify our observers.
   io_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&Helper::OnProxyConfigChanged, helper_.get(), new_config));
 }
 
 void ProxyConfigServiceMac::OnProxyConfigChanged(
     const ProxyConfig& new_config) {
-  DCHECK(io_thread_task_runner_->BelongsToCurrentThread());
+  DCHECK(io_thread_task_runner_->RunsTasksInCurrentSequence());
 
   // Keep track of the last value we have seen.
   has_fetched_config_ = true;
   last_config_fetched_ = new_config;
 
   // Notify all the observers.
   for (auto& observer : observers_)
     observer.OnProxyConfigChanged(new_config, CONFIG_VALID);
 }
 
 }  // namespace net