[WIP] bindings: Introduce PropertyBag

Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h

Index: Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h
diff --git a/Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h b/Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h
index 0e7d41e240aa3ab099cc162549ff9334a9210c46..0120c5436a679828ddb4d8fcfa769ad73294b74a 100644
--- a/Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h
+++ b/Source/bindings/tests/results/V8TestInterfaceGarbageCollected.h
@@ -7,6 +7,7 @@
 #ifndef V8TestInterfaceGarbageCollected_h
 #define V8TestInterfaceGarbageCollected_h
 
+#include "bindings/core/v8/PropertyBagTraits.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
@@ -130,5 +131,10 @@ inline void v8SetReturnValueFast(const CallbackInfo& callbackInfo, RawPtr<TestIn
     v8SetReturnValueFast(callbackInfo, impl.get(), wrappable);
 }
 
+template <>
+struct PropertyBagTraits<TestInterfaceGarbageCollected> {
+    typedef V8TestInterfaceGarbageCollected type;
+};
+
 } // namespace blink
 #endif // V8TestInterfaceGarbageCollected_h