Extensions: Support forIOThread function schema attribute for IDL files.

tools/json_schema_compiler/test/idl_basics.idl

 // Copyright (c) 2012 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.
 
 // Tests a variety of basic API definition features.
 
 [internal] namespace idl_basics {
   // Enum description
   enum EnumType {
     // comment1
@@ skipping 84 matching lines @@
 
     static long function24();
     static MyType1 function25();
     static MyType1[] function26();
     static EnumType function27();
     static EnumType[] function28();
     static idl_other_namespace.SomeType function29();
     static idl_other_namespace.SomeType[] function30();
 
     [nodefine] static void function31(long switch);
+
+    [forIOThread] static void function32();
   };
 
   interface Events {
     static void onFoo1();
     static void onFoo2(long x);
     static void onFoo2(MyType1 arg);
     static void onFoo3(EnumType type);
   };
 };