[scheduler] Add WakeupBudgetPool.

third_party/WebKit/Source/platform/scheduler/base/task_queue.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_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_
 
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/optional.h"
@@ skipping 202 matching lines @@
   // order greater than the fence from running until either the fence has been
   // removed or a subsequent fence has unblocked some tasks within the queue.
   // Note: delayed tasks get their enqueue order set once their delay has
   // expired, and non-delayed tasks get their enqueue order set when posted.
   virtual void InsertFence(InsertFencePosition position) = 0;
 
   // Removes any previously added fence and unblocks execution of any tasks
   // blocked by it.
   virtual void RemoveFence() = 0;
 
+  virtual bool HasFence() const = 0;
+
+  // Returns true if the queue has a fence which is blocking execution of tasks.
   virtual bool BlockedByFence() const = 0;
 
   virtual void SetObserver(Observer* observer) = 0;
 
  protected:
   ~TaskQueue() override {}
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueue);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_H_