[heap] Explicitly clear mark bits when writing filler for left and right trimming.

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 333 matching lines @@
 
 typedef void (*ObjectSlotCallback)(HeapObject** from, HeapObject* to);
 
 enum ArrayStorageAllocationMode {
   DONT_INITIALIZE_ARRAY_ELEMENTS,
   INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
 };
 
 enum class ClearRecordedSlots { kYes, kNo };
 
-enum class ClearBlackArea { kYes, kNo };
-
 enum class GarbageCollectionReason {
   kUnknown = 0,
   kAllocationFailure = 1,
   kAllocationLimit = 2,
   kContextDisposal = 3,
   kCountersExtension = 4,
   kDebugger = 5,
   kDeserializer = 6,
   kExternalMemoryPressure = 7,
   kFinalizeMarkingViaStackGuard = 8,
@@ skipping 366 matching lines @@
   // FreeSpace objects have a null map after deserialization. Update the map.
   void RepairFreeListsAfterDeserialization();
 
   // Move len elements within a given array from src_index index to dst_index
   // index.
   void MoveElements(FixedArray* array, int dst_index, int src_index, int len);
 
   // Initialize a filler object to keep the ability to iterate over the heap
   // when introducing gaps within pages. If slots could have been recorded in
   // the freed area, then pass ClearRecordedSlots::kYes as the mode. Otherwise,
-  // pass ClearRecordedSlots::kNo. If the filler was created in a black area
-  // we may want to clear the corresponding mark bits with ClearBlackArea::kYes,
-  // which is the default. ClearBlackArea::kNo does not clear the mark bits.
-  void CreateFillerObjectAt(
-      Address addr, int size, ClearRecordedSlots mode,
-      ClearBlackArea black_area_mode = ClearBlackArea::kYes);
+  // pass ClearRecordedSlots::kNo.
+  void CreateFillerObjectAt(Address addr, int size, ClearRecordedSlots mode);
 
   bool CanMoveObjectStart(HeapObject* object);
 
   // Maintain consistency of live bytes during incremental marking.
   void AdjustLiveBytes(HeapObject* object, int by);
 
   // Trim the given array from the left. Note that this relocates the object
   // start and hence is only valid if there is only a single reference to it.
   FixedArrayBase* LeftTrimFixedArray(FixedArrayBase* obj, int elements_to_trim);
 
@@ skipping 1908 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_