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

content/child/child_process.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_CHILD_CHILD_PROCESS_H_
 #define CONTENT_CHILD_CHILD_PROCESS_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/synchronization/waitable_event.h"
-#include "base/task_scheduler/scheduler_worker_pool_params.h"
 #include "base/task_scheduler/task_scheduler.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
 #include "content/common/content_export.h"
 
+namespace base {
+struct TaskSchedulerInitParams;
+}
+
 namespace content {
 class ChildThreadImpl;
 
 // Base class for child processes of the browser process (i.e. renderer and
 // plugin host). This is a singleton object for each child process.
 //
 // During process shutdown the following sequence of actions happens in
 // order.
 //
 // 1. ChildProcess::~ChildProcess() is called.
 //   2. Shutdown event is fired. Background threads should stop.
 //   3. ChildThreadImpl::Shutdown() is called. ChildThread is also deleted.
 //   4. IO thread is stopped.
 // 5. Main message loop exits.
 // 6. Child process is now fully stopped.
 //
 // Note: IO thread outlives the ChildThreadImpl object.
 class CONTENT_EXPORT ChildProcess {
  public:
   // Child processes should have an object that derives from this class.
   // Normally you would immediately call set_main_thread after construction.
-  // |io_thread_priority| is the priority of the IO thread. |worker_pool_params|
-  // and |worker_pool_index_for_traits_callback| are used to initialize
-  // TaskScheduler. TaskScheduler is initialized with default values if these
-  // arguments are left empty.
+  // |io_thread_priority| is the priority of the IO thread.
+  // |task_scheduler_name| and |task_scheduler_init_params| are used to
+  // initialize TaskScheduler. Default params are used if
+  // |task_scheduler_init_params| is nullptr.
   ChildProcess(
       base::ThreadPriority io_thread_priority = base::ThreadPriority::NORMAL,
-      const std::vector<base::SchedulerWorkerPoolParams>& worker_pool_params =
-          std::vector<base::SchedulerWorkerPoolParams>(),
-      base::TaskScheduler::WorkerPoolIndexForTraitsCallback
-          worker_pool_index_for_traits_callback =
-              base::TaskScheduler::WorkerPoolIndexForTraitsCallback());
+      const std::string& task_scheduler_name = "ContentChild",
+      std::unique_ptr<base::TaskSchedulerInitParams>
+          task_scheduler_init_params = nullptr);
   virtual ~ChildProcess();
 
   // May be NULL if the main thread hasn't been set explicitly.
   ChildThreadImpl* main_thread();
 
   // Sets the object associated with the main thread of this process.
   // Takes ownership of the pointer.
   void set_main_thread(ChildThreadImpl* thread);
 
   base::MessageLoop* io_message_loop() { return io_thread_.message_loop(); }
@@ skipping 47 matching lines @@
 
   // Whether this ChildProcess initialized TaskScheduler.
   bool initialized_task_scheduler_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(ChildProcess);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_CHILD_PROCESS_H_