[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 9918fef172093785a8d9103d4980b02f8f5548d7..9a674c56c1beb8fb7abab47fddec8ac69d6d5bcb 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -629,6 +629,7 @@ class MarkCompactCollector {
   class EvacuateRecordOnlyVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
+  class ObjectStatsVisitor;
 
   explicit MarkCompactCollector(Heap* heap);
 
@@ -639,6 +640,8 @@ class MarkCompactCollector {
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
 
+  void VisitAllObjects(HeapObjectVisitor* visitor);
+
   // Finishes GC, performs heap verification if enabled.
   void Finish();