Avoid calling v8::Isolate::GetCurrent() twice in V8HiddenPropertyName

Source/bindings/v8/V8HiddenPropertyName.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 53 matching lines @@
 class V8HiddenPropertyName {
 public:
     V8HiddenPropertyName() { }
 #define V8_DECLARE_PROPERTY(name) static v8::Handle<v8::String> name();
     V8_HIDDEN_PROPERTIES(V8_DECLARE_PROPERTY);
 #undef V8_DECLARE_PROPERTY
 
     static void setNamedHiddenReference(v8::Handle<v8::Object> parent, const char* name, v8::Handle<v8::Value> child);
 
 private:
-    static void createString(const char* key, v8::Persistent<v8::String>* handle);
+    static void createString(const char* key, v8::Persistent<v8::String>* handle, v8::Isolate*);
 #define V8_DECLARE_FIELD(name) v8::Persistent<v8::String> m_##name;
     V8_HIDDEN_PROPERTIES(V8_DECLARE_FIELD);
 #undef V8_DECLARE_FIELD
 };
 
 }
 
 #endif // V8HiddenPropertyName_h