Add "own" symbols support.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index cfac520acc6092074855baece99b4e1cf0f7decc..098087aeef555c6d057e9b278383532edbcb87a0 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3371,6 +3371,7 @@ bool Name::Equals(Handle<Name> one, Handle<Name> two) {
 ACCESSORS(Symbol, name, Object, kNameOffset)
 ACCESSORS(Symbol, flags, Smi, kFlagsOffset)
 BOOL_ACCESSORS(Symbol, flags, is_private, kPrivateBit)
+BOOL_ACCESSORS(Symbol, flags, is_own, kOwnBit)
 
 
 bool String::Equals(String* other) {
@@ -6504,6 +6505,10 @@ uint32_t Name::Hash() {
   return String::cast(this)->ComputeAndSetHash();
 }
 
+bool Name::IsOwn() {
+  return this->IsSymbol() && Symbol::cast(this)->is_own();
+}
+
 
 StringHasher::StringHasher(int length, uint32_t seed)
   : length_(length),