[Reland] Optimize blink scheduler with an intrusive heap

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

Index: third_party/WebKit/Source/platform/scheduler/base/work_queue_sets.h
diff --git a/third_party/WebKit/Source/platform/scheduler/base/work_queue_sets.h b/third_party/WebKit/Source/platform/scheduler/base/work_queue_sets.h
index 8fa2c5d18886969e4b76edbc5c0d488d4a414180..75a12b08cd73113c5edc25b9a38bc873b9e15000 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/work_queue_sets.h
+++ b/third_party/WebKit/Source/platform/scheduler/base/work_queue_sets.h
@@ -13,6 +13,7 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "platform/scheduler/base/intrusive_heap.h"
 #include "platform/scheduler/base/task_queue_impl.h"
 #include "public/platform/WebCommon.h"
 
@@ -55,7 +56,7 @@ class BLINK_PLATFORM_EXPORT WorkQueueSets {
   bool IsSetEmpty(size_t set_index) const;
 
 #if DCHECK_IS_ON() || !defined(NDEBUG)
-  // Note this iterates over everything in |enqueue_order_to_work_queue_maps_|.
+  // Note this iterates over everything in |work_queue_heaps_|.
   // It's intended for use with DCHECKS and for testing
   bool ContainsWorkQueueForTest(const WorkQueue* queue) const;
 #endif
@@ -63,8 +64,9 @@ class BLINK_PLATFORM_EXPORT WorkQueueSets {
   const char* name() const { return name_; }
 
  private:
-  typedef std::map<EnqueueOrder, WorkQueue*> EnqueueOrderToWorkQueueMap;
-  std::vector<EnqueueOrderToWorkQueueMap> enqueue_order_to_work_queue_maps_;
+  struct HeapElement;
+
+  std::vector<IntrusiveHeap<HeapElement>> work_queue_heaps_;

[Sami, 2016/10/14 07:26:16]

WDYT of:

using EnqueueOrderToWorkQueueHeap = IntrusiveHeap<HeapElement>;
std::vector<EnqueueOrderToWorkQueueHeap> work_queue_heaps_;?

(I'm trying to make it more obvious to the casual reader what these data
structures contain. Another name for HeapElement might be good too but I'm
drawing a blank.)

[alex clarke (OOO till 29th), 2016/10/14 13:55:36]

Perhaps OldestTaskEnqueueOrder?  That is what we're sorting by.

   const char* name_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkQueueSets);