Clear next map word when folding allocations into js arrays.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5758 matching lines @@
 
   void SetEnumLength(int length) {
     if (length != kInvalidEnumCache) {
       ASSERT(length >= 0);
       ASSERT(length == 0 || instance_descriptors()->HasEnumCache());
       ASSERT(length <= NumberOfOwnDescriptors());
     }
     set_bit_field3(EnumLengthBits::update(bit_field3(), length));
   }
 
-  inline bool CanTrackAllocationSite();
   inline bool owns_descriptors();
   inline void set_owns_descriptors(bool is_shared);
   inline bool is_observed();
   inline void set_is_observed(bool is_observed);
   inline void freeze();
   inline bool is_frozen();
   inline void mark_unstable();
   inline bool is_stable();
   inline void set_migration_target(bool value);
   inline bool is_migration_target();
@@ skipping 2048 matching lines @@
     return transition_info()->IsJSArray();
   }
 
   DECLARE_PRINTER(AllocationSite)
   DECLARE_VERIFIER(AllocationSite)
 
   static inline AllocationSite* cast(Object* obj);
   static inline AllocationSiteMode GetMode(
       ElementsKind boilerplate_elements_kind);
   static inline AllocationSiteMode GetMode(ElementsKind from, ElementsKind to);
+  static inline bool CanTrack(InstanceType type);
 
   static const int kTransitionInfoOffset = HeapObject::kHeaderSize;
   static const int kWeakNextOffset = kTransitionInfoOffset + kPointerSize;
   static const int kSize = kWeakNextOffset + kPointerSize;
 
   typedef FixedBodyDescriptor<HeapObject::kHeaderSize,
                               kTransitionInfoOffset + kPointerSize,
                               kSize> BodyDescriptor;
 
  private:
@@ skipping 2348 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_