Update PPAPI IDL generator to define versioned structs, and unversioned typedef.

ppapi/api/ppb_core.idl

-/* Copyright (c) 2011 The Chromium Authors. All rights reserved.
+/* 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.
  */
 
 /**
  * This file defines the <code>PPB_Core</code> interface defined by the browser
  * and containing pointers to functions related to memory management, time, and
  * threads.
  */
 
@@ skipping 80 matching lines @@
    *
    * This function is useful for implementing sanity checks, and deciding if
    * dispatching using CallOnMainThread() is required.
    *
    * @return A <code>PP_Bool</code> containing <code>PP_TRUE</code> if the
    * current thread is the main pepper thread, otherwise <code>PP_FALSE</code>.
    */
   PP_Bool IsMainThread();
 };