IDL: Drop value conversion (V8 -> C++) macros from generated code

Source/bindings/tests/results/core/V8SVGTestInterface.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file has been auto-generated by code_generator_v8.py. DO NOT MODIFY!
 
 #include "config.h"
 #include "V8SVGTestInterface.h"
 
 #include "bindings/core/v8/ExceptionState.h"
@@ skipping 31 matching lines @@
 {
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMGetter");
     SVGTestInterfaceV8Internal::typeAttributeGetter(info);
     TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution");
 }
 
 static void typeAttributeSetter(v8::Local<v8::Value> v8Value, const v8::PropertyCallbackInfo<void>& info)
 {
     v8::Local<v8::Object> holder = info.Holder();
     SVGTestInterface* impl = V8SVGTestInterface::toImpl(holder);
-    TOSTRING_VOID(V8StringResource<>, cppValue, v8Value);
+    TONATIVE_DECLARE(V8StringResource<>, cppValue, (cppValue = v8Value).prepare(), return);
     CustomElementProcessingStack::CallbackDeliveryScope deliveryScope;
     impl->setAttribute(SVGNames::typeAttr, cppValue);
 }
 
 static void typeAttributeSetterCallback(v8::Local<v8::String>, v8::Local<v8::Value> v8Value, const v8::PropertyCallbackInfo<void>& info)
 {
     TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMSetter");
     CustomElementProcessingStack::CallbackDeliveryScope deliveryScope;
     SVGTestInterfaceV8Internal::typeAttributeSetter(v8Value, info);
     TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution");
@@ skipping 47 matching lines @@
 {
     scriptWrappable->toImpl<SVGTestInterface>()->ref();
 }
 
 void V8SVGTestInterface::derefObject(ScriptWrappable* scriptWrappable)
 {
     scriptWrappable->toImpl<SVGTestInterface>()->deref();
 }
 
 } // namespace blink