Revert of [Reland] Scheduler refactoring to virtually eliminate redundant DoWorks

third_party/WebKit/Source/platform/scheduler/base/time_domain.h

Index: third_party/WebKit/Source/platform/scheduler/base/time_domain.h
diff --git a/third_party/WebKit/Source/platform/scheduler/base/time_domain.h b/third_party/WebKit/Source/platform/scheduler/base/time_domain.h
index 4947fd5e0c529a79d0af9cf5a78c04b595d6f6f1..639d1742a35feec99c4355430a72a7ab048b076a 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/time_domain.h
+++ b/third_party/WebKit/Source/platform/scheduler/base/time_domain.h
@@ -62,11 +62,9 @@
   // Evaluate this TimeDomain's Now. Can be called from any thread.
   virtual base::TimeTicks Now() const = 0;
 
-  // Computes the delay until the next task the TimeDomain is aware of, if any.
-  // Note virtual time domains may return base::TimeDelta() if they have any
-  // tasks that are eligible to run.
-  virtual base::Optional<base::TimeDelta> DelayTillNextTask(
-      LazyNow* lazy_now) = 0;
+  // Some TimeDomains support virtual time, this method tells us to advance time
+  // if possible and return true if time was advanced.
+  virtual bool MaybeAdvanceTime() = 0;
 
   // Returns the name of this time domain for tracing.
   virtual const char* GetName() const = 0;
@@ -90,6 +88,10 @@
   // the next task was posted to and it returns true.  Returns false otherwise.
   bool NextScheduledTaskQueue(TaskQueue** out_task_queue) const;
 
+  // Adds |queue| to the set of task queues that UpdateWorkQueues calls
+  // UpdateWorkQueue on.
+  void RegisterAsUpdatableTaskQueue(internal::TaskQueueImpl* queue);
+
   // Schedules a call to TaskQueueImpl::WakeUpForDelayedWork when this
   // TimeDomain reaches |delayed_run_time|.  This supersedes any previously
   // registered wakeup for |queue|.
@@ -100,12 +102,15 @@
   // Registers the |queue|.
   void RegisterQueue(internal::TaskQueueImpl* queue);
 
+  // Removes |queue| from the set of task queues that UpdateWorkQueues calls
+  // UpdateWorkQueue on. Returns true if |queue| was updatable.
+  bool UnregisterAsUpdatableTaskQueue(internal::TaskQueueImpl* queue);
+
   // Removes |queue| from all internal data structures.
   void UnregisterQueue(internal::TaskQueueImpl* queue);
 
-  // Tells the time domain that |queue| went from having no immediate work to
-  // having some.
-  void OnQueueHasImmediateWork(internal::TaskQueueImpl* queue);
+  // Updates active queues associated with this TimeDomain.
+  void UpdateWorkQueues(LazyNow lazy_now);
 
   // Called by the TaskQueueManager when the TimeDomain is registered.
   virtual void OnRegisterWithTaskQueueManager(
@@ -131,6 +136,8 @@
   }
 
  private:
+  void MoveNewlyUpdatableQueuesIntoUpdatableQueueSet();
+
   struct DelayedWakeup {
     base::TimeTicks time;
     internal::TaskQueueImpl* queue;
@@ -157,6 +164,15 @@
 
   IntrusiveHeap<DelayedWakeup> delayed_wakeup_queue_;
 
+  // This lock guards only |newly_updatable_|.  It's not expected to be heavily
+  // contended.
+  base::Lock newly_updatable_lock_;
+  std::vector<internal::TaskQueueImpl*> newly_updatable_;
+
+  // Set of task queues with avaliable work on the incoming queue.  This should
+  // only be accessed from the main thread.
+  std::set<internal::TaskQueueImpl*> updatable_queue_set_;
+
   Observer* observer_;  // NOT OWNED.
 
   base::ThreadChecker main_thread_checker_;