ES6 symbols: Implement Symbol intrinsic and basic functionality

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 590023ec8a775dd2a47dfc3f0d5a98b5f2b3e507..ee954d8ddd1ff7e1368bfe42fc14b3b1c42091fe 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -181,15 +181,19 @@ TYPE_CHECKER(HeapNumber, HEAP_NUMBER_TYPE)
 TYPE_CHECKER(Symbol, SYMBOL_TYPE)
 
 
-bool Object::IsName() {
+bool Object::IsString() {
   return Object::IsHeapObject()
-    && HeapObject::cast(this)->map()->instance_type() <= LAST_NAME_TYPE;
+    && HeapObject::cast(this)->map()->instance_type() < FIRST_NONSTRING_TYPE;
 }
 
 
-bool Object::IsString() {
-  return Object::IsHeapObject()
-    && HeapObject::cast(this)->map()->instance_type() < FIRST_NONSTRING_TYPE;
+bool Object::IsName() {
+  return IsString() || IsSymbol();
+}
+
+
+bool Object::IsUniqueName() {
+  return IsInternalizedString() || IsSymbol();
 }