scheduler: Move the Blink scheduler into Blink

components/scheduler/renderer/throttling_helper.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 COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
-#define COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
-
-#include <set>
-
-#include "base/macros.h"
-#include "components/scheduler/base/cancelable_closure_holder.h"
-#include "components/scheduler/base/time_domain.h"
-#include "components/scheduler/scheduler_export.h"
-#include "third_party/WebKit/public/platform/WebViewScheduler.h"
-
-namespace scheduler {
-
-class RendererSchedulerImpl;
-class ThrottledTimeDomain;
-class WebFrameSchedulerImpl;
-
-class SCHEDULER_EXPORT ThrottlingHelper : public TimeDomain::Observer {
- public:
-  ThrottlingHelper(RendererSchedulerImpl* renderer_scheduler,
-                   const char* tracing_category);
-
-  ~ThrottlingHelper() override;
-
-  // TimeDomain::Observer implementation:
-  void OnTimeDomainHasImmediateWork() override;
-  void OnTimeDomainHasDelayedWork() override;
-
-  // The purpose of this method is to make sure throttling doesn't conflict with
-  // enabling/disabling the queue for policy reasons.
-  // If |task_queue| is throttled then the ThrottlingHelper remembers the
-  // |enabled| setting.  In addition if |enabled| is false then the queue is
-  // immediatly disabled.  Otherwise if |task_queue| not throttled then
-  // TaskQueue::SetEnabled(enabled) is called.
-  void SetQueueEnabled(TaskQueue* task_queue, bool enabled);
-
-  // Increments the throttled refcount and causes |task_queue| to be throttled
-  // if its not already throttled.
-  void IncreaseThrottleRefCount(TaskQueue* task_queue);
-
-  // If the refcouint is non-zero it's decremented.  If the throttled refcount
-  // becomes zero then |task_queue| is unthrottled.  If the refcount was already
-  // zero this function does nothing.
-  void DecreaseThrottleRefCount(TaskQueue* task_queue);
-
-  // Removes |task_queue| from |throttled_queues_|.
-  void UnregisterTaskQueue(TaskQueue* task_queue);
-
-  const ThrottledTimeDomain* time_domain() const { return time_domain_.get(); }
-
-  static base::TimeTicks ThrottledRunTime(base::TimeTicks unthrottled_runtime);
-
-  const scoped_refptr<TaskQueue>& task_runner() const { return task_runner_; }
-
- private:
-  struct Metadata {
-    Metadata() : throttling_ref_count(0), enabled(false) {}
-
-    Metadata(size_t ref_count, bool is_enabled)
-        : throttling_ref_count(ref_count), enabled(is_enabled) {}
-
-    size_t throttling_ref_count;
-    bool enabled;
-  };
-  using TaskQueueMap = std::map<TaskQueue*, Metadata>;
-
-  void PumpThrottledTasks();
-
-  // Note |unthrottled_runtime| might be in the past. When this happens we
-  // compute the delay to the next runtime based on now rather than
-  // unthrottled_runtime.
-  void MaybeSchedulePumpThrottledTasksLocked(
-      const tracked_objects::Location& from_here,
-      base::TimeTicks now,
-      base::TimeTicks unthrottled_runtime);
-
-  TaskQueueMap throttled_queues_;
-  base::Closure forward_immediate_work_closure_;
-  scoped_refptr<TaskQueue> task_runner_;
-  RendererSchedulerImpl* renderer_scheduler_;  // NOT OWNED
-  base::TickClock* tick_clock_;                // NOT OWNED
-  const char* tracing_category_;               // NOT OWNED
-  std::unique_ptr<ThrottledTimeDomain> time_domain_;
-
-  CancelableClosureHolder suspend_timers_when_backgrounded_closure_;
-  base::TimeTicks pending_pump_throttled_tasks_runtime_;
-
-  base::WeakPtrFactory<ThrottlingHelper> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(ThrottlingHelper);
-};
-
-}  // namespace scheduler
-
-#endif  // COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_