[Try # 3] Scheduler refactoring to virtually eliminate redundant DoWorks

third_party/WebKit/Source/platform/scheduler/base/task_queue_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 THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 121 matching lines @@
       base::MessageLoop::TaskObserver* task_observer) override;
   void SetTimeDomain(TimeDomain* time_domain) override;
   TimeDomain* GetTimeDomain() const override;
   void SetBlameContext(base::trace_event::BlameContext* blame_context) override;
   void InsertFence(InsertFencePosition position) override;
   void RemoveFence() override;
   bool BlockedByFence() const override;
   const char* GetName() const override;
   QueueType GetQueueType() const override;
 
-  // If this returns false then future updates for this queue are not needed
-  // unless requested.
-  bool MaybeUpdateImmediateWorkQueues();
+  // As BlockedByFence but only safe to be called while |any_thread_| is locked.
+  // Must only be called from the thread this task queue was created on.
+  bool BlockedByFenceLocked() const;
+
+  // Must only be called from the thread this task queue was created on.
+  void OnImmediateWorkQueueHasBecomeEmpty(
+      std::queue<TaskQueueImpl::Task>* work_queue);
+
+  // Must only be called from the thread this task queue was created on.
+  void ReloadImmediateWorkQueueIfEmpty();
 
   void AsValueInto(base::trace_event::TracedValue* state) const;
 
   bool GetQuiescenceMonitored() const { return should_monitor_quiescence_; }
   bool GetShouldNotifyObservers() const { return should_notify_observers_; }
 
   void NotifyWillProcessTask(const base::PendingTask& pending_task);
   void NotifyDidProcessTask(const base::PendingTask& pending_task);
 
   WorkQueue* delayed_work_queue() {
@@ skipping 10 matching lines @@
 
   const WorkQueue* immediate_work_queue() const {
     return main_thread_only().immediate_work_queue.get();
   }
 
   bool should_report_when_execution_blocked() const {
     return should_report_when_execution_blocked_;
   }
 
   // Enqueues any delayed tasks which should be run now on the
-  // |delayed_work_queue|. It also schedules the next wake up with the
-  // TimeDomain. Must be called from the main thread.
-  void WakeUpForDelayedWork(LazyNow* lazy_now);
+  // |delayed_work_queue|. Returns the deadline if a subsequent wakeup is
+  // required. Must be called from the main thread.
+  base::Optional<base::TimeTicks> WakeUpForDelayedWork(LazyNow* lazy_now);
 
   base::TimeTicks scheduled_time_domain_wakeup() const {
     return main_thread_only().scheduled_time_domain_wakeup;
   }
 
   void set_scheduled_time_domain_wakeup(
       base::TimeTicks scheduled_time_domain_wakeup) {
     main_thread_only().scheduled_time_domain_wakeup =
         scheduled_time_domain_wakeup;
   }
@@ skipping 95 matching lines @@
   // Push the task onto the |immediate_incoming_queue| and for auto pumped
   // queues it calls MaybePostDoWorkOnMainRunner if the Incoming queue was
   // empty.
   void PushOntoImmediateIncomingQueueLocked(
       const tracked_objects::Location& posted_from,
       const base::Closure& task,
       base::TimeTicks desired_run_time,
       EnqueueOrder sequence_number,
       bool nestable);
 
-  // As BlockedByFence but safe to be called while locked.
-  bool BlockedByFenceLocked() const;
-
   void TraceQueueSize(bool is_locked) const;
   static void QueueAsValueInto(const std::queue<Task>& queue,
                                base::trace_event::TracedValue* state);
   static void QueueAsValueInto(const std::priority_queue<Task>& queue,
                                base::trace_event::TracedValue* state);
   static void TaskAsValueInto(const Task& task,
                               base::trace_event::TracedValue* state);
 
   void RemoveQueueEnabledVoter(const QueueEnabledVoterImpl* voter);
   void OnQueueEnabledVoteChanged(bool enabled);
@@ skipping 33 matching lines @@
   const bool should_report_when_execution_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueImpl);
 };
 
 }  // namespace internal
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_IMPL_H_