[heap] Reland Concurrently free empty typed slot set chunks.

src/heap/remembered-set.cc

 // Copyright 2016 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.
 
 #include "src/heap/remembered-set.h"
 #include "src/heap/heap-inl.h"
 #include "src/heap/heap.h"
 #include "src/heap/mark-compact.h"
 #include "src/heap/slot-set.h"
 #include "src/heap/spaces.h"
@@ skipping 18 matching lines @@
   for (MemoryChunk* chunk : *heap->code_space()) {
     TypedSlotSet* slots = GetTypedSlotSet(chunk);
     if (slots != nullptr) {
       slots->Iterate(
           [heap, chunk](SlotType type, Address host_addr, Address addr) {
             if (Marking::IsBlack(ObjectMarking::MarkBitFrom(host_addr))) {
               return KEEP_SLOT;
             } else {
               return REMOVE_SLOT;
             }
-          });
+          },
+          TypedSlotSet::PREFREE_EMPTY_CHUNKS);
     }
   }
   for (MemoryChunk* chunk : *heap->map_space()) {
     SlotSet* slots = GetSlotSet(chunk);
     if (slots != nullptr) {
       slots->Iterate([heap, chunk](Address addr) {
         Object** slot = reinterpret_cast<Object**>(addr);
         // TODO(mlippautz): In map space all allocations would ideally be map
         // aligned. After establishing this invariant IsValidSlot could just
         // refer to the containing object using alignment and check the mark
@@ skipping 42 matching lines @@
          heap->mark_compact_collector()->IsSlotInBlackObject(
              chunk, reinterpret_cast<Address>(slot));
 }
 
 template void RememberedSet<OLD_TO_NEW>::ClearInvalidSlots(Heap* heap);
 template void RememberedSet<OLD_TO_NEW>::VerifyValidSlots(Heap* heap);
 template void RememberedSet<OLD_TO_OLD>::VerifyValidSlots(Heap* heap);
 
 }  // namespace internal
 }  // namespace v8