IDL: Add support for serializer definitions

tools/idl_parser/test_parser/interface_web.idl

 /* Copyright (c) 2013 The Chromium Authors. All rights reserved.
    Use of this source code is governed by a BSD-style license that can be
   found in the LICENSE file. */
 
 /* Test Interface productions
 
 Run with --test to generate an AST and verify that all comments accurately
 reflect the state of the Nodes.
 
 BUILD Type(Name)
@@ skipping 305 matching lines @@
  *    Type()
  *      PrimitiveType(long)
  *  Setlike()
  *    Type()
  *      PrimitiveType(double)
  */
 interface MyIfaceSetlike {
   readonly setlike<long>;
   setlike<double>;
 };
+
+/* TREE
+ *Interface(MyIfaceSerializer)
+ *  Serializer()
+ *  Serializer()
+ *    Operation(toJSON)
+ *      Arguments()
+ *      Type()
+ *        Any()
+ *  Serializer()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    Map()
+ *  Serializer()
+ *    List()
+ *  Serializer()
+ *    List()
+ *  Serializer()
+ *    List()
+ */
+interface MyIfaceSerializer {
+  serializer;
+  serializer any toJSON();
+  serializer = name;
+  serializer = {};
+  serializer = { getter };
+  serializer = { attribute };
+  serializer = { inherit, attribute };
+  serializer = { inherit };
+  serializer = { inherit, name1, name2 };
+  serializer = { name1, name2 };
+  serializer = [];
+  serializer = [getter];
+  serializer = [name1, name2];
+};