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

Source/bindings/v8/WorkerScriptController.h

Index: Source/bindings/v8/WorkerScriptController.h
diff --git a/Source/bindings/v8/WorkerScriptController.h b/Source/bindings/v8/WorkerScriptController.h
index cd452e33c44d5f225f8aa3d38e9710b5a45442af..5b46cf9ed7c84d6496075c5ef5d121018d0c3ad3 100644
--- a/Source/bindings/v8/WorkerScriptController.h
+++ b/Source/bindings/v8/WorkerScriptController.h
@@ -91,7 +91,7 @@ namespace WebCore {
         ScriptValue evaluate(const String& script, const String& fileName, const TextPosition& scriptStartPosition, WorkerGlobalScopeExecutionState*);
 
         v8::Isolate* isolate() const { return m_isolate; }
-        DOMWrapperWorld* world() const { return m_world.get(); }
+        DOMWrapperWorld& world() const { return *m_world; }
         v8::Local<v8::Context> context() { return m_perContextData ? m_perContextData->context() : v8::Local<v8::Context>(); }
 
         // Send a notification about current thread is going to be idle.