[heap] Rework and improve object stats tracing

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index e14a457dadf8ee532c46343e020fc6ca3c6c4d84..969ab11cf38e05efa7ad4a3cfe9a614a14a6494b 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -501,6 +501,7 @@ class MarkCompactCollector {
   class EvacuateRecordOnlyVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
+  class ObjectStatsVisitor;
 
   explicit MarkCompactCollector(Heap* heap);
 
@@ -511,6 +512,8 @@ class MarkCompactCollector {
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
 
+  void VisitAllObjects(HeapObjectVisitor* visitor);
+
   // Finishes GC, performs heap verification if enabled.
   void Finish();