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

Source/bindings/v8/V8PerIsolateData.cpp

 /*
  * Copyright (C) 2009 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 77 matching lines @@
 
 void V8PerIsolateData::dispose(v8::Isolate* isolate)
 {
     void* data = isolate->GetData(gin::kEmbedderBlink);
     delete static_cast<V8PerIsolateData*>(data);
     isolate->SetData(gin::kEmbedderBlink, 0);
 }
 
 V8PerIsolateData::DOMTemplateMap& V8PerIsolateData::currentDOMTemplateMap()
 {
-    if (DOMWrapperWorld::current(m_isolate).isMainWorld())
+    if (DOMWrapperWorld::current(m_isolate)->isMainWorld())
         return m_domTemplateMapForMainWorld;
     return m_domTemplateMapForNonMainWorld;
 }
 
 v8::Handle<v8::FunctionTemplate> V8PerIsolateData::domTemplate(void* domTemplateKey, v8::FunctionCallback callback, v8::Handle<v8::Value> data, v8::Handle<v8::Signature> signature, int length)
 {
     DOMTemplateMap& domTemplateMap = currentDOMTemplateMap();
     DOMTemplateMap::iterator result = domTemplateMap.find(domTemplateKey);
     if (result != domTemplateMap.end())
         return result->value.Get(m_isolate);
@@ skipping 77 matching lines @@
 }
 
 v8::Handle<v8::FunctionTemplate> V8PerIsolateData::toStringTemplate()
 {
     if (m_toStringTemplate.isEmpty())
         m_toStringTemplate.set(m_isolate, v8::FunctionTemplate::New(m_isolate, constructorOfToString));
     return m_toStringTemplate.newLocal(m_isolate);
 }
 
 } // namespace WebCore