Remove TaskTraits::with_file_io().

ios/web/app/web_main_loop.mm

 // 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 "ios/web/app/web_main_loop.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 60 matching lines @@
   DCHECK_EQ(WORKER_POOL_COUNT, params_vector.size());
   return params_vector;
 }
 
 // Returns the worker pool index for |traits| defaulting to FOREGROUND or
 // FOREGROUND_FILE_IO on any other priorities based off of worker pools defined
 // in GetDefaultSchedulerWorkerPoolParams().
 size_t DefaultBrowserWorkerPoolIndexForTraits(const base::TaskTraits& traits) {
   const bool is_background =
       traits.priority() == base::TaskPriority::BACKGROUND;
-  if (traits.with_file_io())
+  if (traits.may_block() || traits.with_base_sync_primitives())
     return is_background ? BACKGROUND_FILE_IO : FOREGROUND_FILE_IO;
 
   return is_background ? BACKGROUND : FOREGROUND;
 }
 
 }  // namespace
 
 // The currently-running WebMainLoop.  There can be one or zero.
 // TODO(rohitrao): Desktop uses this to implement
 // ImmediateShutdownAndExitProcess.  If we don't need that functionality, we can
@@ skipping 244 matching lines @@
   main_thread_.reset(
       new WebThreadImpl(WebThread::UI, base::MessageLoop::current()));
 }
 
 int WebMainLoop::WebThreadsStarted() {
   cookie_notification_bridge_.reset(new CookieNotificationBridge);
   return result_code_;
 }
 
 }  // namespace web