Refactor TimeDomain::MaybeAdvanceTime in preparation for DoWork deduping

third_party/WebKit/Source/platform/scheduler/base/time_domain.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_TIME_DOMAIN_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TIME_DOMAIN_H_
 
 #include <map>
 
 #include "base/callback.h"
@@ skipping 44 matching lines @@
   virtual ~TimeDomain();
 
   // Returns a LazyNow that evaluate this TimeDomain's Now.  Can be called from
   // any thread.
   // TODO(alexclarke): Make this main thread only.
   virtual LazyNow CreateLazyNow() const = 0;
 
   // Evaluate this TimeDomain's Now. Can be called from any thread.
   virtual base::TimeTicks Now() const = 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;
+  // 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
+  // delayed tasks they deem eligible to run.  Virtual time domains are allowed
+  // to advance their internal clock when this method is called.
+  virtual base::Optional<base::TimeDelta> DelayTillNextTask(
+      LazyNow* lazy_now) = 0;
 
   // Returns the name of this time domain for tracing.
   virtual const char* GetName() const = 0;
 
   // If there is a scheduled delayed task, |out_time| is set to the scheduled
   // runtime for the next one and it returns true.  Returns false otherwise.
   bool NextScheduledRunTime(base::TimeTicks* out_time) const;
 
  protected:
   friend class internal::TaskQueueImpl;
@@ skipping 25 matching lines @@
   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);
 
   // Updates active queues associated with this TimeDomain.
-  void UpdateWorkQueues(LazyNow lazy_now);
+  void UpdateWorkQueues(LazyNow* lazy_now);
 
   // Called by the TaskQueueManager when the TimeDomain is registered.
   virtual void OnRegisterWithTaskQueueManager(
       TaskQueueManager* task_queue_manager) = 0;
 
   // The implementaion will secedule task processing to run with |delay| with
   // respect to the TimeDomain's time source.  Always called on the main thread.
   // NOTE this is only called by ScheduleDelayedWork if the scheduled runtime
   // is sooner than any previously sheduled work or if there is no other
   // scheduled work.
@@ skipping 53 matching lines @@
 
   base::ThreadChecker main_thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeDomain);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TIME_DOMAIN_H_