Integrate map marking into static marking visitor.

src/objects-visiting.h

Index: src/objects-visiting.h
diff --git a/src/objects-visiting.h b/src/objects-visiting.h
index 76a0f74e8603c8819be9d1cd0300819fa3fc6416..7a3b3f4a935a82c9e649ebc63be641cae3ecebc7 100644
--- a/src/objects-visiting.h
+++ b/src/objects-visiting.h
@@ -398,9 +398,15 @@ class StaticMarkingVisitor : public StaticVisitorBase {
   static inline void VisitNativeContext(Map* map, HeapObject* object);
 
  protected:
+  static inline void VisitMap(Map* map, HeapObject* object);
   static inline void VisitCode(Map* map, HeapObject* object);
   static inline void VisitJSRegExp(Map* map, HeapObject* object);
 
+  // Mark pointers in a Map and its TransitionArray together, possibly
+  // treating transitions or back pointers weak.
+  static void MarkMapContents(Heap* heap, Map* map);
+  static void MarkTransitionArray(Heap* heap, TransitionArray* transitions);
+
   class DataObjectVisitor {
    public:
     template<int size>