v8::Private::ForApi should be context-independent.

src/runtime/runtime-symbol.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/isolate-inl.h"
 #include "src/objects-inl.h"
 #include "src/string-builder.h"
@@ skipping 38 matching lines @@
   IncrementalStringBuilder builder(isolate);
   builder.AppendCString("Symbol(");
   if (symbol->name()->IsString()) {
     builder.AppendString(handle(String::cast(symbol->name()), isolate));
   }
   builder.AppendCharacter(')');
   RETURN_RESULT_OR_FAILURE(isolate, builder.Finish());
 }
 
 
-RUNTIME_FUNCTION(Runtime_SymbolRegistry) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 0);
-  return *isolate->GetSymbolRegistry();
-}
-
-
 RUNTIME_FUNCTION(Runtime_SymbolIsPrivate) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Symbol, symbol, 0);
   return isolate->heap()->ToBoolean(symbol->is_private());
 }
 }  // namespace internal
 }  // namespace v8