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tools/dom/scripts/idlnode.py

Index: tools/dom/scripts/idlnode.py
diff --git a/tools/dom/scripts/idlnode.py b/tools/dom/scripts/idlnode.py
index 953d27424bfb493801b331f0aea92a0ec038c8aa..60a6ef7ddbf8e0977d7b3783287323a59d96726f 100755
--- a/tools/dom/scripts/idlnode.py
+++ b/tools/dom/scripts/idlnode.py
@@ -308,7 +308,7 @@ class IDLExtAttrs(IDLDictNode):
 
       func_value = self._find_first(value, 'ExtAttrFunctionValue')
       if func_value:
-        # E.g. NamedConstructor=Audio(in [Optional] DOMString src)
+        # E.g. NamedConstructor=Audio(optional DOMString src)
         self[name] = IDLExtAttrFunctionValue(
             func_value,
             self._find_first(func_value, 'ExtAttrArgList'))
@@ -497,6 +497,7 @@ class IDLArgument(IDLNode):
   def __init__(self, ast):
     IDLNode.__init__(self, ast)
     self.type = self._convert_first(ast, 'Type', IDLType)
+    self.optional = self._has(ast, 'Optional')
     self._convert_ext_attrs(ast)
 
   def __repr__(self):