Use TaskScheduler instead of SequencedWorkerPool in breakpad_helper.mm.

ios/chrome/browser/crash_report/breakpad_helper.mm

 // 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 "ios/chrome/browser/crash_report/breakpad_helper.h"
 
 #import <Foundation/Foundation.h>
 #include <stddef.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/debug/crash_logging.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/task_scheduler/post_task.h"
 #include "ios/chrome/browser/chrome_paths.h"
 #import "ios/chrome/browser/crash_report/crash_report_user_application_state.h"
-#include "ios/web/public/web_thread.h"
 
 // TODO(stuartmorgan): Move this up where it belongs once
 // http://code.google.com/p/google-breakpad/issues/detail?id=487
 // is fixed. For now, put it at the end to avoid compiler errors.
 #import "breakpad/src/client/ios/BreakpadController.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
@@ skipping 139 matching lines @@
 
 bool IsUploadingEnabled() {
   // Return the value cached by CacheUploadingEnabled().
   return [[NSUserDefaults standardUserDefaults]
       boolForKey:kCrashReportsUploadingEnabledKey];
 }
 
 void CleanupCrashReports() {
   base::FilePath crash_directory;
   PathService::Get(ios::DIR_CRASH_DUMPS, &crash_directory);
-  web::WebThread::PostBlockingPoolTask(
-      FROM_HERE, base::Bind(&DeleteAllReportsInDirectory, crash_directory));
+  base::PostTaskWithTraits(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BACKGROUND},
+      base::BindOnce(&DeleteAllReportsInDirectory, crash_directory));
 }
 
 void AddReportParameter(NSString* key, NSString* value, bool async) {
   if (!g_crash_reporter_enabled)
     return;
   if (async) {
     [[BreakpadController sharedInstance] addUploadParameter:value forKey:key];
     return;
   }
   dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
@@ skipping 156 matching lines @@
 void RestoreDefaultConfiguration() {
   if (!g_crash_reporter_enabled)
     return;
   [[BreakpadController sharedInstance] stop];
   [[BreakpadController sharedInstance] resetConfiguration];
   [[BreakpadController sharedInstance] start:NO];
   [[BreakpadController sharedInstance] setUploadingEnabled:NO];
 }
 
 }  // namespace breakpad_helper