Change RecordSlot interface. Make it more robust by replacing anchor slot with actual object.

src/heap/heap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 934 matching lines @@
   void IterateRoots(ObjectVisitor* v, VisitMode mode);
   // Iterates over all strong roots in the heap.
   void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
   // Iterates over entries in the smi roots list.  Only interesting to the
   // serializer/deserializer, since GC does not care about smis.
   void IterateSmiRoots(ObjectVisitor* v);
   // Iterates over all the other roots in the heap.
   void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
 
   // Iterate pointers to from semispace of new space found in memory interval
-  // from start to end.
-  void IterateAndMarkPointersToFromSpace(bool record_slots, Address start,
-                                         Address end,
+  // from start to end within |object|.
+  void IterateAndMarkPointersToFromSpace(HeapObject* object, Address start,
+                                         Address end, bool record_slots,
                                          ObjectSlotCallback callback);
 
   // Returns whether the object resides in new space.
   inline bool InNewSpace(Object* object);
   inline bool InNewSpace(Address address);
   inline bool InNewSpacePage(Address address);
   inline bool InFromSpace(Object* object);
   inline bool InToSpace(Object* object);
 
   // Returns whether the object resides in old space.
@@ skipping 1864 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_