Add an idle task to periodically sweep canceled delayed tasks

third_party/WebKit/Source/platform/scheduler/child/scheduler_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 THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 68 matching lines @@
     // queue. See TaskQueue::Spec::SetShouldReportWhenExecutionBlocked.
     virtual void OnTriedToExecuteBlockedTask(const TaskQueue& queue,
                                              const base::PendingTask& task) = 0;
   };
 
   // Called once to set the Observer. This function is called on the main
   // thread. If |observer| is null, then no callbacks will occur.
   // Note |observer| is expected to outlive the SchedulerHelper.
   void SetObserver(Observer* observer);
 
+  // Remove all canceled delayed tasks.
+  void SweepCanceledDelayedTasks();
+
   // Accessor methods.
   RealTimeDomain* real_time_domain() const;
   void RegisterTimeDomain(TimeDomain* time_domain);
   void UnregisterTimeDomain(TimeDomain* time_domain);
   const scoped_refptr<SchedulerTqmDelegate>& scheduler_tqm_delegate() const;
   bool GetAndClearSystemIsQuiescentBit();
   TaskQueue* CurrentlyExecutingTaskQueue() const;
 
   size_t GetNumberOfPendingTasks() const;
 
@@ skipping 14 matching lines @@
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerHelper);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_CHILD_SCHEDULER_HELPER_H_