Start incremental marking in long idle notification for background tab

src/heap/heap.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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 2261 matching lines @@
 
   GCIdleTimeHandler::HeapState ComputeHeapState();
 
   bool PerformIdleTimeAction(GCIdleTimeAction action,
                              GCIdleTimeHandler::HeapState heap_state,
                              double deadline_in_ms);
 
   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);
 
   inline void UpdateAllocationsHash(HeapObject* object);
   inline void UpdateAllocationsHash(uint32_t value);
   inline void PrintAlloctionsHash();
 
   void AddToRingBuffer(const char* string);
   void GetFromRingBuffer(char* buffer);
 
@@ skipping 573 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_