IDL: make optional arguments (without default) explicit sometimes

Source/modules/webaudio/AudioNode.idl

Index: Source/modules/webaudio/AudioNode.idl
diff --git a/Source/modules/webaudio/AudioNode.idl b/Source/modules/webaudio/AudioNode.idl
index 41396a38b3ae772350807e4633b89b8a6c0f6ba6..599379e1c2ffdb63a891cc10f736118ad804f32d 100644
--- a/Source/modules/webaudio/AudioNode.idl
+++ b/Source/modules/webaudio/AudioNode.idl
@@ -41,9 +41,9 @@ enum ChannelInterpretation {
     GarbageCollected,
 ] interface AudioNode : EventTarget {
     // FIXME: AudioNode argument should not be nullable
-    [RaisesException] void connect(AudioNode? destination, [Default=Undefined] optional unsigned long output, [Default=Undefined] optional unsigned long input);
-    [RaisesException] void connect(AudioParam destination, [Default=Undefined] optional unsigned long output);
-    [RaisesException] void disconnect([Default=Undefined] optional unsigned long output);
+    [RaisesException] void connect(AudioNode? destination, optional unsigned long output, optional unsigned long input);
+    [RaisesException] void connect(AudioParam destination, optional unsigned long output);
+    [RaisesException] void disconnect(optional unsigned long output);
     readonly attribute AudioContext  context;
     readonly attribute unsigned long numberOfInputs;
     readonly attribute unsigned long numberOfOutputs;