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

Source/bindings/tests/results/modules/UnionTypesModules.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 "bindings/modules/v8/UnionTypesModules.h"
 
 
@@ skipping 48 matching lines @@
 {
     if (v8Value.IsEmpty())
         return;
 
     if (v8Value->IsBoolean()) {
         impl.setBoolean(v8Value->ToBoolean()->Value());
         return;
     }
 
     {
-        TOSTRING_VOID_EXCEPTIONSTATE(V8StringResource<>, cppValue, v8Value, exceptionState);
+        V8StringResource<> cppValue = v8Value;
+        if (!cppValue.prepare(exceptionState))
+            return;
         impl.setString(cppValue);
         return;
     }
 
 }
 
 v8::Local<v8::Value> toV8(const BooleanOrString& impl, v8::Local<v8::Object> creationContext, v8::Isolate* isolate)
 {
     switch (impl.m_type) {
     case BooleanOrString::SpecificTypeNone:
         return v8::Null(isolate);
     case BooleanOrString::SpecificTypeBoolean:
         return v8Boolean(impl.getAsBoolean(), isolate);
     case BooleanOrString::SpecificTypeString:
         return v8String(isolate, impl.getAsString());
     default:
         ASSERT_NOT_REACHED();
     }
     return v8::Local<v8::Value>();
 }
 
 BooleanOrString NativeValueTraits<BooleanOrString>::nativeValue(const v8::Local<v8::Value>& value, v8::Isolate* isolate, ExceptionState& exceptionState)
 {
     BooleanOrString impl;
     V8BooleanOrString::toImpl(isolate, value, impl, exceptionState);
     return impl;
 }
 
 } // namespace blink