IDL: Improve "includes for type" mechanism in various ways

Source/bindings/tests/results/core/V8TestInterfaceConstructor.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 "V8TestInterfaceConstructor.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/UnionTypesCore.h"
 #include "bindings/core/v8/V8DOMConfiguration.h"
 #include "bindings/core/v8/V8ObjectConstructor.h"
+#include "bindings/core/v8/V8TestDictionary.h"
 #include "bindings/core/v8/V8TestInterfaceEmpty.h"
 #include "core/dom/ContextFeatures.h"
 #include "core/dom/Document.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/UseCounter.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/TraceEvent.h"
 #include "wtf/GetPtr.h"
 #include "wtf/RefPtr.h"
 
@@ skipping 350 matching lines @@
 {
     scriptWrappable->toImpl<TestInterfaceConstructor>()->ref();
 }
 
 void V8TestInterfaceConstructor::derefObject(ScriptWrappable* scriptWrappable)
 {
     scriptWrappable->toImpl<TestInterfaceConstructor>()->deref();
 }
 
 } // namespace blink