[reference - do not submit] Always create four pools in TaskSchedulerImpl.

components/task_scheduler_util/renderer/initialization.cc

 // Copyright 2017 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/renderer/initialization.h"
 
-#include <map>
-#include <string>
-
 #include "base/command_line.h"
-#include "base/logging.h"
-#include "base/task_scheduler/task_traits.h"
-#include "base/threading/platform_thread.h"
+#include "base/memory/ptr_util.h"
 #include "components/task_scheduler_util/common/variations_util.h"
 
 namespace task_scheduler_util {
 
-namespace {
+std::unique_ptr<base::TaskSchedulerInitParams>
+GetRendererTaskSchedulerInitParamsFromCommandLine() {
+  auto variation_params = GetVariationParamsFromCommandLine(
+      *base::CommandLine::ForCurrentProcess());
 
-enum WorkerPoolType : size_t {
-  BACKGROUND = 0,
-  BACKGROUND_BLOCKING,
-  FOREGROUND,
-  FOREGROUND_BLOCKING,
-  WORKER_POOL_COUNT  // Always last.
-};
+  auto init_params = base::MakeUnique<base::TaskSchedulerInitParams>(
+      StringToVariableWorkerPoolParams(variation_params["RendererBackground"]),
+      StringToVariableWorkerPoolParams(
+          variation_params["RendererBackgroundBlocking"]),
+      StringToVariableWorkerPoolParams(variation_params["RendererForeground"]),
+      StringToVariableWorkerPoolParams(
+          variation_params["RendererForegroundBlocking"]));
 
-}  // namespace
+  if (init_params->IsValid())
+    return init_params;
 
-std::vector<base::SchedulerWorkerPoolParams> GetRendererWorkerPoolParams() {
-  using ThreadPriority = base::ThreadPriority;
-  std::vector<SchedulerImmutableWorkerPoolParams> immutable_worker_pool_params;
-  DCHECK_EQ(BACKGROUND, immutable_worker_pool_params.size());
-  immutable_worker_pool_params.emplace_back("RendererBackground",
-                                            ThreadPriority::BACKGROUND);
-  DCHECK_EQ(BACKGROUND_BLOCKING, immutable_worker_pool_params.size());
-  immutable_worker_pool_params.emplace_back("RendererBackgroundBlocking",
-                                            ThreadPriority::BACKGROUND);
-  DCHECK_EQ(FOREGROUND, immutable_worker_pool_params.size());
-  immutable_worker_pool_params.emplace_back("RendererForeground",
-                                            ThreadPriority::NORMAL);
-  DCHECK_EQ(FOREGROUND_BLOCKING, immutable_worker_pool_params.size());
-  immutable_worker_pool_params.emplace_back("RendererForegroundBlocking",
-                                            ThreadPriority::NORMAL);
-  return GetWorkerPoolParams(immutable_worker_pool_params,
-                             GetVariationParamsFromCommandLine(
-                                 *base::CommandLine::ForCurrentProcess()));
-}
-
-size_t RendererWorkerPoolIndexForTraits(const base::TaskTraits& traits) {
-  const bool is_background =
-      traits.priority() == base::TaskPriority::BACKGROUND;
-  if (traits.may_block() || traits.with_base_sync_primitives())
-    return is_background ? BACKGROUND_BLOCKING : FOREGROUND_BLOCKING;
-  return is_background ? BACKGROUND : FOREGROUND;
+  return nullptr;
 }
 
 }  // namespace task_scheduler_util