[Reland] Optimize blink scheduler with an intrusive heap

third_party/WebKit/Source/platform/scheduler/base/work_queue.h

Index: third_party/WebKit/Source/platform/scheduler/base/work_queue.h
diff --git a/third_party/WebKit/Source/platform/scheduler/base/work_queue.h b/third_party/WebKit/Source/platform/scheduler/base/work_queue.h
index f6e520608d1855941e0b794b58fff0060ded7122..a6859f4ca92c3152fd100de3121404f5afc125c3 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/work_queue.h
+++ b/third_party/WebKit/Source/platform/scheduler/base/work_queue.h
@@ -82,6 +82,10 @@ class BLINK_PLATFORM_EXPORT WorkQueue {
 
   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();
 
@@ -112,6 +116,7 @@ class BLINK_PLATFORM_EXPORT WorkQueue {
   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_;