Use idle task to perform incremental marking steps.

src/heap/incremental-marking.h

 // Copyright 2012 the V8 project 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 V8_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 
+#include "src/cancelable-task.h"
 #include "src/execution.h"
 #include "src/heap/mark-compact.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 
 class IncrementalMarking {
  public:
@@ skipping 178 matching lines @@
   void ClearIdleMarkingDelayCounter();
 
   bool IsIdleMarkingDelayCounterLimitReached();
 
   INLINE(static void MarkObject(Heap* heap, HeapObject* object));
 
   Heap* heap() const { return heap_; }
 
   GCCallbackFlags CallbackFlags() const { return gc_callback_flags_; }
 
+  void ScheduleIncrementalMarkingTask();
+  void NotifyIncrementalMarkingTaskRunning();
+  bool IsIncrementalMarkingTaskPending() {
+    return pending_incremental_marking_task_;
+  }
+
  private:
   int64_t SpaceLeftInOldSpace();
 
   void SpeedUp();
 
   void ResetStepCounters();
 
   void StartMarking();
 
   void ActivateIncrementalWriteBarrier(PagedSpace* space);
@@ skipping 40 matching lines @@
   bool was_activated_;
 
   bool weak_closure_was_overapproximated_;
 
   int weak_closure_approximation_rounds_;
 
   GCRequestType request_type_;
 
   GCCallbackFlags gc_callback_flags_;
 
+  bool pending_incremental_marking_task_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
+
+
+class IncrementalMarkingTask : public CancelableIdleTask {
+ public:
+  explicit IncrementalMarkingTask(Isolate* isolate)
+      : CancelableIdleTask(isolate) {}
+  // CancelableIdleTask overrides.
+  void RunInternal(double deadline_in_seconds) override;
+  enum Progress { kDone, kMoreWork };
+  static Progress Step(Heap* heap, double deadline_in_ms);
+};
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_