Support FrozenArray in idl_parser.py

tools/idl_parser/test_parser/interface_web.idl

Index: tools/idl_parser/test_parser/interface_web.idl
diff --git a/tools/idl_parser/test_parser/interface_web.idl b/tools/idl_parser/test_parser/interface_web.idl
index 90b0e83e8433707692fc00457aed1dfe056d0f6b..a2c9ae6346609a1e54ed0db50108489bc9eab497 100644
--- a/tools/idl_parser/test_parser/interface_web.idl
+++ b/tools/idl_parser/test_parser/interface_web.idl
@@ -369,3 +369,15 @@ interface MyIfaceSerializer {
   serializer = [getter];
   serializer = [name1, name2];
 };
+
+/* TREE
+ *Interface(MyIfaceFrozenArray)
+ *  Attribute(foo)
+ *    Type()
+ *      FrozenArray()
+ *        Type()
+ *          PrimitiveType(DOMString)
+ */
+interface MyIfaceFrozenArray {
+  readonly attribute FrozenArray<DOMString> foo;
+};