Prevent redundant DoWorks due to canceled delayed tasks (v2)

third_party/WebKit/Source/platform/scheduler/base/virtual_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_VIRTUAL_TIME_DOMAIN_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_VIRTUAL_TIME_DOMAIN_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "platform/scheduler/base/time_domain.h"
@@ skipping 11 matching lines @@
   LazyNow CreateLazyNow() const override;
   base::TimeTicks Now() const override;
   bool MaybeAdvanceTime() override;
   const char* GetName() const override;
 
   // Advances this time domain to |now|. NOTE |now| is supposed to be
   // monotonically increasing.  NOTE it's the responsibility of the caller to
   // call TaskQueueManager::MaybeScheduleImmediateWork if needed.
   void AdvanceTo(base::TimeTicks now);
 
-  using TimeDomain::ClearExpiredWakeups;
-
  protected:
   void OnRegisterWithTaskQueueManager(
       TaskQueueManager* task_queue_manager) override;
   void RequestWakeup(base::TimeTicks now, base::TimeDelta delay) override;
   void AsValueIntoInternal(
       base::trace_event::TracedValue* state) const override;
 
   void RequestDoWork();
 
  private:
   mutable base::Lock lock_;  // Protects |now_|.
   base::TimeTicks now_;
 
   TaskQueueManager* task_queue_manager_;  // NOT OWNED
   base::Closure do_work_closure_;
 
   DISALLOW_COPY_AND_ASSIGN(VirtualTimeDomain);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_VIRTUAL_TIME_DOMAIN_H_