[Reland] Optimize blink scheduler with an intrusive heap

third_party/WebKit/Source/platform/scheduler/base/work_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_WORK_QUEUE_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_WORK_QUEUE_H_
 
 #include <stddef.h>
 
 #include <set>
@@ skipping 64 matching lines @@
   TaskQueueImpl::Task TakeTaskFromWorkQueue();
 
   const char* name() const { return name_; }
 
   TaskQueueImpl* task_queue() const { return task_queue_; }
 
   WorkQueueSets* work_queue_sets() const { return work_queue_sets_; }
 
   size_t work_queue_set_index() const { return work_queue_set_index_; }
 
+  size_t heap_index() const { return heap_index_; }
+
+  void set_heap_index(size_t heap_index) { heap_index_ = heap_index; }
+
   // Test support function. This should not be used in production code.
   void PopTaskForTest();
 
   // Returns true if the front task in this queue has an older enqueue order
   // than the front task of |other_queue|. Both queue are assumed to be
   // non-empty. This method ignores any fences.
   bool ShouldRunBefore(const WorkQueue* other_queue) const;
 
   // Submit a fence. When TakeTaskFromWorkQueue encounters a task whose
   // enqueue_order is >= |fence| then the WorkQueue will start pretending to be.
@@ skipping 10 matching lines @@
   // Returns true if any tasks are blocked by the fence. Returns true if the
   // queue is empty and fence has been set (i.e. future tasks would be blocked).
   // Otherwise returns false.
   bool BlockedByFence() const;
 
  private:
   std::queue<TaskQueueImpl::Task> work_queue_;
   WorkQueueSets* work_queue_sets_;  // NOT OWNED.
   TaskQueueImpl* task_queue_;       // NOT OWNED.
   size_t work_queue_set_index_;
+  size_t heap_index_;
   const char* name_;
   EnqueueOrder fence_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkQueue);
 };
 
 }  // namespace internal
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_WORK_QUEUE_H_