Revert of Make DOMWrapperWorld::current() return a reference instead of a pointer

Source/bindings/v8/custom/V8CustomEventCustom.cpp

 /*
  * 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 74 matching lines @@
 
     V8TRYCATCH_FOR_V8STRINGRESOURCE_VOID(V8StringResource<>, typeArg, info[0]);
     V8TRYCATCH_VOID(bool, canBubbleArg, info[1]->BooleanValue());
     V8TRYCATCH_VOID(bool, cancelableArg, info[2]->BooleanValue());
     v8::Handle<v8::Value> detailsArg = info[3];
 
     event->initEvent(typeArg, canBubbleArg, cancelableArg);
 
     if (!detailsArg.IsEmpty()) {
         V8HiddenValue::setHiddenValue(info.GetIsolate(), info.Holder(), V8HiddenValue::detail(info.GetIsolate()), detailsArg);
-        if (DOMWrapperWorld::current(info.GetIsolate()).isIsolatedWorld())
+        if (DOMWrapperWorld::current(info.GetIsolate())->isIsolatedWorld())
             event->setSerializedDetail(SerializedScriptValue::createAndSwallowExceptions(detailsArg, info.GetIsolate()));
     }
 }
 
 } // namespace WebCore