[Cleanup] Migrate the StatisticsProvider to use the TaskScheduler

chrome/browser/metrics/chromeos_metrics_provider.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/metrics/chromeos_metrics_provider.h"
 
 #include <stddef.h>
 
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/post_task.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/threading/thread_restrictions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/arc/arc_session_manager.h"
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
 #include "chrome/common/chrome_features.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/system/statistics_provider.h"
 #include "components/metrics/leak_detector/leak_detector.h"
 #include "components/metrics/metrics_service.h"
 #include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/user_manager/user_manager.h"
-#include "content/public/browser/browser_thread.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "ui/display/display.h"
 #include "ui/events/event_utils.h"
 
 #if defined(USE_X11)
 #include "ui/events/devices/x11/touch_factory_x11.h"
 #endif  // defined(USE_X11)
 
@@ skipping 123 matching lines @@
   registered_user_count_at_log_initialization_ = false;
   if (user_manager::UserManager::IsInitialized()) {
     registered_user_count_at_log_initialization_ = true;
     user_count_at_log_initialization_ =
         user_manager::UserManager::Get()->GetLoggedInUsers().size();
   }
 }
 
 void ChromeOSMetricsProvider::InitTaskGetHardwareClass(
     const base::Closure& callback) {
-  // Run the (potentially expensive) task on the FILE thread to avoid blocking
+  // Run the (potentially expensive) task in the background to avoid blocking
   // the UI thread.
-  content::BrowserThread::PostTaskAndReply(
-      content::BrowserThread::FILE,
+  base::PostTaskWithTraitsAndReply(
       FROM_HERE,
-      base::Bind(&ChromeOSMetricsProvider::InitTaskGetHardwareClassOnFileThread,
-                 weak_ptr_factory_.GetWeakPtr()),
+      {base::MayBlock(), base::TaskPriority::BACKGROUND,
+       base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN},
+      base::BindOnce(
+          &ChromeOSMetricsProvider::InitTaskGetHardwareClassOnBackgroundThread,
+          weak_ptr_factory_.GetWeakPtr()),
       callback);
 }
 
-void ChromeOSMetricsProvider::InitTaskGetHardwareClassOnFileThread() {
-  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
+void ChromeOSMetricsProvider::InitTaskGetHardwareClassOnBackgroundThread() {
+  base::ThreadRestrictions::AssertWaitAllowed();
   chromeos::system::StatisticsProvider::GetInstance()->GetMachineStatistic(
       "hardware_class", &hardware_class_);
 }
 
 void ChromeOSMetricsProvider::InitTaskGetBluetoothAdapter(
     const base::Closure& callback) {
   device::BluetoothAdapterFactory::GetAdapter(
       base::Bind(&ChromeOSMetricsProvider::SetBluetoothAdapter,
                  weak_ptr_factory_.GetWeakPtr(), callback));
 }
@@ skipping 142 matching lines @@
 void ChromeOSMetricsProvider::RecordEnrollmentStatus() {
   UMA_HISTOGRAM_ENUMERATION(
       "UMA.EnrollmentStatus", GetEnrollmentStatus(), ENROLLMENT_STATUS_MAX);
 }
 
 void ChromeOSMetricsProvider::RecordArcState() {
   arc::ArcSessionManager* arc_session_manager = arc::ArcSessionManager::Get();
   if (arc_session_manager)
     arc_session_manager->RecordArcState();
 }