Pepper: Autogenerate thunk for PPB_Graphics2D.

ppapi/api/dev/ppb_graphics_2d_dev.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.
  */
 
 /* This file contains the <code>PPB_Graphics2D_Dev</code> interface. */
+
+[generate_thunk]
+
 label Chrome {
   M22 = 0.1
 };
 
 /* PPB_Graphics2D_Dev interface */
 interface PPB_Graphics2D_Dev {
   /**
    * SetScale() sets the scale factor that will be applied when painting the
    * graphics context onto the output device. Typically, if rendering at device
    * resolution is desired, the context would be created with the width and
@@ skipping 20 matching lines @@
    *
    * @param[in] resource A <code>Graphics2D</code> context resource.
    *
    * @return Returns the scale factor for the graphics context. If the resource
    * is not a valid <code>Graphics2D</code> context, this will return 0.0.
    */
   float_t GetScale(
       [in] PP_Resource resource);
 };