[heap] Drop filler objects on marking deque.

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/heap.h"
@@ skipping 268 matching lines @@
   static void DeactivateIncrementalWriteBarrierForSpace(NewSpace* space);
   void DeactivateIncrementalWriteBarrier();
 
   static void SetOldSpacePageFlags(MemoryChunk* chunk, bool is_marking,
                                    bool is_compacting);
 
   static void SetNewSpacePageFlags(MemoryChunk* chunk, bool is_marking);
 
   INLINE(void ProcessMarkingDeque());
 
-  INLINE(intptr_t ProcessMarkingDeque(intptr_t bytes_to_process));
+  INLINE(intptr_t ProcessMarkingDeque(
+      intptr_t bytes_to_process,
+      ForceCompletionAction completion = DO_NOT_FORCE_COMPLETION));
 
   INLINE(void VisitObject(Map* map, HeapObject* obj, int size));
 
   void IncrementIdleMarkingDelayCounter();
 
   Heap* heap_;
 
   Observer observer_;
 
   State state_;
@@ skipping 23 matching lines @@
   GCRequestType request_type_;
 
   IncrementalMarkingJob incremental_marking_job_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_