Split browser-specific and generic code in components/task_scheduler_util/.

components/task_scheduler_util/browser/initialization.cc

+// 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.
+
+#include "components/task_scheduler_util/browser/initialization.h"
+
+#include <map>
+#include <string>
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/task_scheduler/scheduler_worker_pool_params.h"
+#include "base/task_scheduler/switches.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/threading/platform_thread.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "components/task_scheduler_util/common/variations_util.h"
+#include "components/variations/variations_associated_data.h"
+
+namespace task_scheduler_util {
+
+namespace {
+
+constexpr char kFieldTrialName[] = "BrowserScheduler";
+
+enum WorkerPoolType : size_t {
+  BACKGROUND = 0,
+  BACKGROUND_FILE_IO,
+  FOREGROUND,
+  FOREGROUND_FILE_IO,
+  WORKER_POOL_COUNT  // Always last.
+};
+
+}  // namespace
+
+std::vector<base::SchedulerWorkerPoolParams>
+GetBrowserWorkerPoolParamsFromVariations() {
+  using ThreadPriority = base::ThreadPriority;
+
+  std::map<std::string, std::string> variation_params;
+  if (!::variations::GetVariationParams(kFieldTrialName, &variation_params))
+    return {};
+
+  std::vector<SchedulerImmutableWorkerPoolParams> constant_worker_pool_params;
+  DCHECK_EQ(BACKGROUND, constant_worker_pool_params.size());
+  constant_worker_pool_params.emplace_back("Background",
+                                           ThreadPriority::BACKGROUND);
+  DCHECK_EQ(BACKGROUND_FILE_IO, constant_worker_pool_params.size());
+  constant_worker_pool_params.emplace_back("BackgroundFileIO",
+                                           ThreadPriority::BACKGROUND);
+  DCHECK_EQ(FOREGROUND, constant_worker_pool_params.size());
+  constant_worker_pool_params.emplace_back("Foreground",
+                                           ThreadPriority::NORMAL);
+  DCHECK_EQ(FOREGROUND_FILE_IO, constant_worker_pool_params.size());
+  constant_worker_pool_params.emplace_back("ForegroundFileIO",
+                                           ThreadPriority::NORMAL);
+
+  return GetWorkerPoolParams(constant_worker_pool_params, variation_params);
+}
+
+size_t BrowserWorkerPoolIndexForTraits(const base::TaskTraits& traits) {
+  const bool is_background =
+      traits.priority() == base::TaskPriority::BACKGROUND;
+  if (traits.with_file_io())
+    return is_background ? BACKGROUND_FILE_IO : FOREGROUND_FILE_IO;
+  return is_background ? BACKGROUND : FOREGROUND;
+}
+
+void MaybePerformBrowserTaskSchedulerRedirection() {
+  // TODO(gab): Remove this when http://crbug.com/622400 concludes.
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableBrowserTaskScheduler) &&
+      variations::GetVariationParamValue(
+          kFieldTrialName, "RedirectSequencedWorkerPools") == "true") {
+    base::SequencedWorkerPool::EnableWithRedirectionToTaskSchedulerForProcess();
+  }
+}
+
+}  // namespace task_scheduler_util