Avoid manual object's body traversal in GC.

src/heap/mark-compact.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_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 398 matching lines @@
   INLINE(void ForceRecordSlot(HeapObject* object, Object** slot,
                               Object* target));
 
   void UpdateSlots(SlotsBuffer* buffer);
   void UpdateSlotsRecordedIn(SlotsBuffer* buffer);
 
   void MigrateObject(HeapObject* dst, HeapObject* src, int size,
                      AllocationSpace to_old_space,
                      SlotsBuffer** evacuation_slots_buffer);
 
-  void MigrateObjectTagged(HeapObject* dst, HeapObject* src, int size,
-                           SlotsBuffer** evacuation_slots_buffer);
-  void MigrateObjectMixed(HeapObject* dst, HeapObject* src, int size,
-                          SlotsBuffer** evacuation_slots_buffer);
-  void MigrateObjectRaw(HeapObject* dst, HeapObject* src, int size);
-
   bool TryPromoteObject(HeapObject* object, int object_size);
 
   void InvalidateCode(Code* code);
 
   void ClearMarkbits();
 
   bool is_compacting() const { return compacting_; }
 
   MarkingParity marking_parity() { return marking_parity_; }
 
@@ skipping 128 matching lines @@
   // -----------------------------------------------------------------------
   // Phase 1: Marking live objects.
   //
   //  Before: The heap has been prepared for garbage collection by
   //          MarkCompactCollector::Prepare() and is otherwise in its
   //          normal state.
   //
   //   After: Live objects are marked and non-live objects are unmarked.
 
   friend class CodeMarkingVisitor;
+  friend class IncrementalMarkingMarkingVisitor;
   friend class MarkCompactMarkingVisitor;
   friend class MarkingVisitor;
+  friend class RecordMigratedSlotVisitor;
   friend class RootMarkingVisitor;
   friend class SharedFunctionInfoMarkingVisitor;
-  friend class IncrementalMarkingMarkingVisitor;
 
   // Mark code objects that are active on the stack to prevent them
   // from being flushed.
   void PrepareThreadForCodeFlushing(Isolate* isolate, ThreadLocalTop* top);
 
   void PrepareForCodeFlushing();
 
   // Marking operations for objects reachable from roots.
   void MarkLiveObjects();
 
@@ skipping 274 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_