Remove old APIs from components/task_scheduler_util/.

components/task_scheduler_util/initialization/browser_util.h

-// Copyright 2016 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.
-
-// TODO(fdoray): Remove this file once TaskScheduler initialization in the
-// browser process uses the components/task_scheduler_util/browser/ API on all
-// platforms.
-
-#ifndef COMPONENTS_TASK_SCHEDULER_UTIL_INITIALIZATION_BROWSER_UTIL_H_
-#define COMPONENTS_TASK_SCHEDULER_UTIL_INITIALIZATION_BROWSER_UTIL_H_
-
-#include <stddef.h>
-
-namespace base {
-class TaskTraits;
-}
-
-namespace task_scheduler_util {
-namespace initialization {
-
-// Maps |traits| to the index of a browser worker pool vector provided by
-// BrowserWorkerPoolConfigurationToSchedulerWorkerPoolParams() or
-// GetDefaultBrowserSchedulerWorkerPoolParams().
-size_t BrowserWorkerPoolIndexForTraits(const base::TaskTraits& traits);
-
-}  // namespace initialization
-}  // namespace task_scheduler_util
-
-#endif  // COMPONENTS_TASK_SCHEDULER_UTIL_INITIALIZATION_BROWSER_UTIL_H_