Add the boilerplate for actions to File System Provider API.

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 13 matching lines @@
     DOMString z;
     DOMString a;
     DOMString b;
     DOMString c;
   };
 
   dictionary MyType2 {
     DOMString x;
   };
 
+  dictionary UnionType {
+    (EnumType or DOMString)? x;
+    (DOMString or EnumType) y;
+  };
+
   callback Callback1 = void();
   callback Callback2 = void(long x);
   callback Callback3 = void(MyType1 arg);
   callback Callback4 = void(MyType2[] arg);
   callback Callback5 = void(EnumType type);
   // A comment on a callback.
   // |x|: A parameter.
   callback Callback6 = void(long x);
   // |x|: Just a parameter comment, with no comment on the callback.
   callback Callback7 = void(long x);
@@ skipping 53 matching lines @@
     static idl_other_namespace.SomeType[] function30();
   };
 
   interface Events {
     static void onFoo1();
     static void onFoo2(long x);
     static void onFoo2(MyType1 arg);
     static void onFoo3(EnumType type);
   };
 };