Add an idle task to periodically sweep canceled delayed tasks

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 194 matching lines @@
 
     TaskQueueImpl* GetTaskQueueForTest() const { return task_queue_.get(); }
 
    private:
     friend class TaskQueueImpl;
 
     scoped_refptr<TaskQueueImpl> task_queue_;
     bool enabled_;
   };
 
+  // Iterates over |delayed_incoming_queue| removing canceled tasks.
+  void SweepCanceledDelayedTasks(base::TimeTicks now);
+
  private:
   friend class WorkQueue;
   friend class WorkQueueTest;
 
   enum class TaskType {
     NORMAL,
     NON_NESTABLE,
   };
 
   struct AnyThread {
@@ skipping 115 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_