[heap] Provide ObjectMarking with marking transitions

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index b1536cdf6237437753e2492464bafabb7fa7976f..11bdd33c198cefbd59115fe836e473ba3004a43c 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -3171,6 +3171,7 @@ void Heap::AdjustLiveBytes(HeapObject* object, int by) {
 FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
                                          int elements_to_trim) {
   CHECK_NOT_NULL(object);
+  DCHECK(CanMoveObjectStart(object));
   DCHECK(!object->IsFixedTypedArrayBase());
   DCHECK(!object->IsByteArray());
   const int element_size = object->IsFixedArray() ? kPointerSize : kDoubleSize;
@@ -3221,7 +3222,6 @@ FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
   // Initialize header of the trimmed array. Since left trimming is only
   // performed on pages which are not concurrently swept creating a filler
   // object does not require synchronization.
-  DCHECK(CanMoveObjectStart(object));
   Object** former_start = HeapObject::RawField(object, 0);
   int new_start_index = elements_to_trim * (element_size / kPointerSize);
   former_start[new_start_index] = map;
@@ -4287,7 +4287,7 @@ void Heap::RegisterReservationsForBlackAllocation(Reservation* reservations) {
         Address addr = chunk.start;
         while (addr < chunk.end) {
           HeapObject* obj = HeapObject::FromAddress(addr);
-          Marking::MarkBlack(ObjectMarking::MarkBitFrom(obj));
+          ObjectMarking::WhiteToBlack(obj);
           addr += obj->Size();
         }
       }