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

ppapi/api/ppb.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 a function pointer type for the
  * <code>PPB_GetInterface</code> function.
  */
 
 /**
  * This function pointer type defines the signature for the
  * <code>PPB_GetInterface</code> function. A generic
  * <code>PPB_GetInterface</code> pointer is passed to
  * <code>PPP_InitializedModule</code> when your module is loaded. You can use
  * this pointer to request a pointer to a specific browser interface. Browser
  * interface names are ASCII strings and are generally defined in the header
  * file for the interface, such as <code>PPB_AUDIO_INTERFACE</code> found in
  * <code>ppb.audio.h</code> or
  * <code>PPB_GRAPHICS_2D_INTERFACE</code> in <code>ppb_graphics_2d.h</code>.
  * Click
  * <a href="/chrome/nativeclient/docs/reference/pepperc/globals_defs.html" 
  * title="macros">here</a> for a complete list of interface
  * names.
  *
  * This value will be NULL if the interface is not supported on the browser.
  */
 typedef interface_t PPB_GetInterface([in] str_t interface_name);