[WIP] bindings: Introduce PropertyBag

Source/bindings/templates/dictionary_v8.h

 // 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}}. DO NOT MODIFY!
 
 #ifndef {{v8_class}}_h
 #define {{v8_class}}_h
 
 {% for filename in header_includes %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace blink {
 
+class ExceptionState;
+
 class {{v8_class}} {
 public:
-    static {{cpp_class}}* toImpl(v8::Isolate*, v8::Handle<v8::Value>);
+    static {{cpp_class}}* toImpl(v8::Isolate*, v8::Handle<v8::Value>, ExceptionState&);
 };
 
 v8::Handle<v8::Value> toV8({{cpp_class}}*, v8::Handle<v8::Object>, v8::Isolate*);
 
 template<class CallbackInfo>
 inline void v8SetReturnValue(const CallbackInfo& callbackInfo, {{cpp_class}}* impl)
 {
     v8SetReturnValue(callbackInfo, toV8(impl, callbackInfo.Holder(), callbackInfo.GetIsolate()));
 }
 
 } // namespace blink
 
 #endif // {{v8_class}}_h