Move throttling of background timers into the renderer scheduler

components/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 COMPONENTS_SCHEDULER_BASE_TIME_DOMAIN_H_
 #define COMPONENTS_SCHEDULER_BASE_TIME_DOMAIN_H_
 
 #include <map>
 
 #include "base/callback.h"
@@ skipping 25 matching lines @@
   // 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;
 
   // 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;
 
+  class SCHEDULER_EXPORT Observer {
+   public:
+    virtual ~Observer() {}
+
+    // Called when RegisterAsUpdatableTaskQueue is called. Can fire from any
+    // thread.
+    virtual void OnRegisterAsUpdatableTaskQueue() = 0;

[Sami, 2015/11/24 12:48:48]

How about OnHasNewWork, OnNewIncomingWork, OnNewImmediateWork or something like
that? I think the registration business is really an implementation detail.

Another idea:

OnTimeDomainHasImmediateWork()
OnTimeDomainHasDelayedWork()

[alex clarke (OOO till 29th), 2015/11/25 12:29:36]

Done.

+
+    // Called when RequestWakeup is called. Called only from the main thread.
+    virtual void OnRequestWakeup() = 0;
+  };
+
+  void SetObserver(Observer* observer);
+
  protected:
   friend class internal::TaskQueueImpl;
   friend class TaskQueueManager;
   friend class base::RefCounted<TimeDomain>;
 
   virtual ~TimeDomain();
 
   void AsValueInto(base::trace_event::TracedValue* state) const;
 
   // Migrates |queue| from this time domain to |destination_time_domain|.
@@ skipping 52 matching lines @@
 
   // 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_;
+
   base::ThreadChecker main_thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeDomain);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_BASE_TIME_DOMAIN_H_