Revert of Revert of Add a WorkerScheduler and a WebThreadImplForWorker

content/child/scheduler/worker_scheduler_impl.h

+// Copyright 2015 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_SCHEDULER_WORKER_SCHEDULER_IMPL_H_
+#define CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_IMPL_H_
+
+#include "content/child/scheduler/worker_scheduler.h"
+#include "content/child/scheduler/scheduler_helper.h"
+
+namespace base {
+namespace trace_event {
+class ConvertableToTraceFormat;
+}
+}
+
+namespace content {
+
+class NestableSingleThreadTaskRunner;
+
+class CONTENT_EXPORT WorkerSchedulerImpl
+    : public WorkerScheduler,
+      public SchedulerHelper::SchedulerHelperDelegate {
+ public:
+  explicit WorkerSchedulerImpl(
+      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner);
+  ~WorkerSchedulerImpl() override;
+
+  // WorkerScheduler implementation:
+  scoped_refptr<base::SingleThreadTaskRunner> DefaultTaskRunner() override;
+  scoped_refptr<SingleThreadIdleTaskRunner> IdleTaskRunner() override;
+  bool CanExceedIdleDeadlineIfRequired() const override;
+  void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
+  void RemoveTaskObserver(
+      base::MessageLoop::TaskObserver* task_observer) override;
+  void Init() override;
+  void Shutdown() override;
+
+  void SetTimeSourceForTesting(scoped_refptr<cc::TestNowSource> time_source);
+  void SetWorkBatchSizeForTesting(size_t work_batch_size);
+  base::TimeTicks CurrentIdleTaskDeadlineForTesting() const;
+
+ protected:
+  // SchedulerHelperDelegate implementation:
+  bool CanEnterLongIdlePeriod(
+      base::TimeTicks now,
+      base::TimeDelta* next_long_idle_period_delay_out) override;
+  void IsNotQuiescent() override {}
+
+ private:
+  void MaybeStartLongIdlePeriod();
+
+  SchedulerHelper helper_;
+  bool initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(WorkerSchedulerImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_CHILD_SCHEDULER_WORKER_SCHEDULER_IMPL_H_