[WIP] bindings: Introduce PropertyBag

Source/bindings/templates/dictionary_v8.h

Index: Source/bindings/templates/dictionary_v8.h
diff --git a/Source/bindings/templates/dictionary_v8.h b/Source/bindings/templates/dictionary_v8.h
index 5f6b7803ce2a8f3b9fffac5846c5c03919934eae..a14f2bf79555c3516de17c697870c154ed588558 100644
--- a/Source/bindings/templates/dictionary_v8.h
+++ b/Source/bindings/templates/dictionary_v8.h
@@ -13,9 +13,11 @@
 
 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*);