Remove @@create and don't expose unimplemented symbols

src/symbol.js

 // Copyright 2013 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.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 64 matching lines @@
   }
 
   // TODO(arv): Proxies use a shared trap for String and Symbol keys.
 
   return ObjectGetOwnPropertyKeys(obj, true);
 }
 
 
 //-------------------------------------------------------------------
 
-var symbolCreate = InternalSymbol("Symbol.create");
 var symbolHasInstance = InternalSymbol("Symbol.hasInstance");
 var symbolIsConcatSpreadable = InternalSymbol("Symbol.isConcatSpreadable");
 var symbolIsRegExp = InternalSymbol("Symbol.isRegExp");
 var symbolIterator = InternalSymbol("Symbol.iterator");
 var symbolToStringTag = InternalSymbol("Symbol.toStringTag");
 var symbolUnscopables = InternalSymbol("Symbol.unscopables");
 
 
 //-------------------------------------------------------------------
 
 function SetUpSymbol() {
   %CheckIsBootstrapping();
 
   %SetCode($Symbol, SymbolConstructor);
   %FunctionSetPrototype($Symbol, new $Object());
 
   InstallConstants($Symbol, $Array(
-    "create", symbolCreate,
-    "hasInstance", symbolHasInstance,
-    "isConcatSpreadable", symbolIsConcatSpreadable,
-    "isRegExp", symbolIsRegExp,
-    "iterator", symbolIterator,
-    "toStringTag", symbolToStringTag,
-    "unscopables", symbolUnscopables
+    // TODO(rossberg): expose when implemented.
+    // "hasInstance", symbolHasInstance,
+    // "isConcatSpreadable", symbolIsConcatSpreadable,
+    // "isRegExp", symbolIsRegExp,
+    "iterator", symbolIterator
+    // "toStringTag", symbolToStringTag,
+    // "unscopables", symbolUnscopables
   ));
   InstallFunctions($Symbol, DONT_ENUM, $Array(
     "for", SymbolFor,
     "keyFor", SymbolKeyFor
   ));
 
   %AddNamedProperty($Symbol.prototype, "constructor", $Symbol, DONT_ENUM);
   InstallFunctions($Symbol.prototype, DONT_ENUM, $Array(
     "toString", SymbolToString,
     "valueOf", SymbolValueOf
   ));
 }
 
 SetUpSymbol();
 
 
 function ExtendObject() {
   %CheckIsBootstrapping();
 
   InstallFunctions($Object, DONT_ENUM, $Array(
     "getOwnPropertySymbols", ObjectGetOwnPropertySymbols
   ));
 }
 
 ExtendObject();