Reland "[heap] Provide ObjectMarking with marking transitions"

src/heap/scavenger.cc

Index: src/heap/scavenger.cc
diff --git a/src/heap/scavenger.cc b/src/heap/scavenger.cc
index d4e191ade48f36f4c136b82c4147fc63c0d5ce04..6111ec5e905bcf866236ff6a04db3ee2fd3eb858 100644
--- a/src/heap/scavenger.cc
+++ b/src/heap/scavenger.cc
@@ -200,9 +200,8 @@ class ScavengingVisitor : public StaticVisitorBase {
                                    reinterpret_cast<base::AtomicWord>(target));
 
       if (object_contents == POINTER_OBJECT) {
-        heap->promotion_queue()->insert(
-            target, object_size,
-            Marking::IsBlack(ObjectMarking::MarkBitFrom(object)));
+        heap->promotion_queue()->insert(target, object_size,
+                                        ObjectMarking::IsBlack(object));
       }
       heap->IncrementPromotedObjectsSize(object_size);
       return true;
@@ -246,8 +245,7 @@ class ScavengingVisitor : public StaticVisitorBase {
     DCHECK(map_word.IsForwardingAddress());
     HeapObject* target = map_word.ToForwardingAddress();
 
-    MarkBit mark_bit = ObjectMarking::MarkBitFrom(target);
-    if (Marking::IsBlack(mark_bit)) {
+    if (ObjectMarking::IsBlack(target)) {
       // This object is black and it might not be rescanned by marker.
       // We should explicitly record code entry slot for compaction because
       // promotion queue processing (IteratePromotedObjectPointers) will