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

Source/bindings/v8/V8PerContextData.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 50 matching lines @@
         V8PerContextDataHolder* holder = static_cast<V8PerContextDataHolder*>(context->GetAlignedPointerFromEmbedderData(v8ContextPerContextDataIndex));
         // V8PerContextDataHolder::from() must not be called for a context that does not have
         // valid embedder data in the embedder field.
         RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(holder);
         RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(holder->context() == context);
         return holder;
     }
 
     V8PerContextData* perContextData() const { return m_perContextData; }
     void setPerContextData(V8PerContextData* data) { m_perContextData = data; }
-    DOMWrapperWorld& world() const { return *m_world; }
+    DOMWrapperWorld* world() const { return m_world.get(); }
     v8::Handle<v8::Context> context() const { return m_context.newLocal(m_isolate); }
 
 private:
     V8PerContextDataHolder(v8::Handle<v8::Context> context, PassRefPtr<DOMWrapperWorld> world)
         : m_isolate(context->GetIsolate())
         , m_context(m_isolate, context)
         , m_perContextData(0)
         , m_world(world)
     {
-        ASSERT(m_world);
         m_context.setWeak(this, &V8PerContextDataHolder::weakCallback);
         context->SetAlignedPointerInEmbedderData(v8ContextPerContextDataIndex, this);
     }
 
     ~V8PerContextDataHolder() { }
 
     static void weakCallback(const v8::WeakCallbackData<v8::Context, V8PerContextDataHolder>& data)
     {
         data.GetValue()->SetAlignedPointerInEmbedderData(v8ContextPerContextDataIndex, 0);
         delete data.GetParameter();
@@ skipping 32 matching lines @@
 
     disposeMapWithUnsafePersistentValues(&m_wrapperBoilerplates);
     disposeMapWithUnsafePersistentValues(&m_constructorMap);
 }
 
 V8PerContextData* V8PerContextData::from(v8::Handle<v8::Context> context)
 {
     return V8PerContextDataHolder::from(context)->perContextData();
 }
 
-DOMWrapperWorld& V8PerContextData::world(v8::Handle<v8::Context> context)
+DOMWrapperWorld* V8PerContextData::world(v8::Handle<v8::Context> context)
 {
-    DOMWrapperWorld& world = V8PerContextDataHolder::from(context)->world();
+    DOMWrapperWorld* world = V8PerContextDataHolder::from(context)->world();
+    ASSERT(world);
     return world;
 }
 
 v8::Local<v8::Object> V8PerContextData::createWrapperFromCacheSlowCase(const WrapperTypeInfo* type)
 {
     ASSERT(!m_errorPrototype.isEmpty());
 
     v8::Context::Scope scope(context());
     v8::Local<v8::Function> function = constructorForType(type);
     v8::Local<v8::Object> instanceTemplate = V8ObjectConstructor::newInstance(function);
@@ skipping 113 matching lines @@
     if (!data->IsString())
         return -1;
     v8::String::Utf8Value utf8(data);
     char* comma = strnstr(*utf8, ",", utf8.length());
     if (!comma)
         return -1;
     return atoi(comma + 1);
 }
 
 } // namespace WebCore