Start incremental marking in long idle notification for background tab

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index 2db6923d684720c491939d3589bb5519d130a5ba..705bd5f0598759e1c2f77b448d5bea6c16cff453 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -2279,6 +2279,8 @@ class Heap {
   void IdleNotificationEpilogue(GCIdleTimeAction action,
                                 GCIdleTimeHandler::HeapState heap_state,
                                 double start_ms, double deadline_in_ms);
+  void CheckAndNotifyBackgroundIdleNotification(double idle_time_in_ms,
+                                                double now_ms);
 
   void ClearObjectStats(bool clear_last_time_stats = false);