IDL: Treat undefined as missing for optional arguments with defaults

Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp

Index: Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp
diff --git a/Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp b/Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp
index 93bd8a8274fc62f43c6f5fa89ec93507b4524e96..2719301cf4455c662656b7839a57da92271ba1fc 100644
--- a/Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp
+++ b/Source/bindings/tests/results/V8TestInterfaceConstructor2.cpp
@@ -93,7 +93,7 @@ static void constructor3(const v8::FunctionCallbackInfo<v8::Value>& info)
         TONATIVE_VOID_INTERNAL(testInterfaceEmptyArg, V8TestInterfaceEmpty::toNativeWithTypeCheck(info.GetIsolate(), info[0]));
         TONATIVE_VOID_EXCEPTIONSTATE_INTERNAL(longArg, toInt32(info[1], exceptionState), exceptionState);
         TOSTRING_VOID_INTERNAL(defaultUndefinedOptionalStringArg, info[2]);
-        if (info.Length() > 3) {
+        if (!info[3]->IsUndefined()) {
             TOSTRING_VOID_INTERNAL(defaultNullStringOptionalStringArg, info[3]);
         } else {
             defaultNullStringOptionalStringArg = nullptr;