Add "own" symbols support.

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/builtins.h"
@@ skipping 8936 matching lines @@
   // Returns a hash value used for the property table
   inline uint32_t Hash();
 
   // Equality operations.
   inline bool Equals(Name* other);
   inline static bool Equals(Handle<Name> one, Handle<Name> two);
 
   // Conversion.
   inline bool AsArrayIndex(uint32_t* index);
 
+  // Whether name can only name own properties.
+  inline bool IsOwn();
+
   DECLARE_CAST(Name)
 
   DECLARE_PRINTER(Name)
 
   // Layout description.
   static const int kHashFieldOffset = HeapObject::kHeaderSize;
   static const int kSize = kHashFieldOffset + kPointerSize;
 
   // Mask constant for checking if a name has a computed hash code
   // and if it is a string that is an array index.  The least significant bit
@@ skipping 55 matching lines @@
 class Symbol: public Name {
  public:
   // [name]: the print name of a symbol, or undefined if none.
   DECL_ACCESSORS(name, Object)
 
   DECL_ACCESSORS(flags, Smi)
 
   // [is_private]: whether this is a private symbol.
   DECL_BOOLEAN_ACCESSORS(is_private)
 
+  // [is_own]: whether this is an own symbol, that is, only used to designate
+  // own properties of objects.
+  DECL_BOOLEAN_ACCESSORS(is_own)
+
   DECLARE_CAST(Symbol)
 
   // Dispatched behavior.
   DECLARE_PRINTER(Symbol)
   DECLARE_VERIFIER(Symbol)
 
   // Layout description.
   static const int kNameOffset = Name::kSize;
   static const int kFlagsOffset = kNameOffset + kPointerSize;
   static const int kSize = kFlagsOffset + kPointerSize;
 
   typedef FixedBodyDescriptor<kNameOffset, kFlagsOffset, kSize> BodyDescriptor;
 
  private:
   static const int kPrivateBit = 0;
+  static const int kOwnBit = 1;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Symbol);
 };
 
 
 class ConsString;
 
 // The String abstract class captures JavaScript string values:
 //
 // Ecma-262:
@@ skipping 2208 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_