Pepper and WebKit API change to support a plugin knowing if a scrollbar is an overlay one.

ppapi/ppapi_shared.gypi

 # Copyright (c) 2011 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.
 
 {
   'targets': [
     {
       'target_name': 'ppapi_shared',
       'type': 'static_library',
       'dependencies': [
@@ skipping 108 matching lines @@
         'thunk/ppb_image_data_thunk.cc',
         'thunk/ppb_image_data_trusted_thunk.cc',
         'thunk/ppb_instance_api.h',
         'thunk/ppb_instance_thunk.cc',
         'thunk/ppb_layer_compositor_api.h',
         'thunk/ppb_layer_compositor_thunk.cc',
         'thunk/ppb_messaging_thunk.cc',
         'thunk/ppb_pdf_api.h',
         'thunk/ppb_query_policy_thunk.cc',
         'thunk/ppb_scrollbar_api.h',
+        'thunk/ppb_scrollbar_group_api.h',
+        'thunk/ppb_scrollbar_group_thunk.cc',
         'thunk/ppb_scrollbar_thunk.cc',
         'thunk/ppb_surface_3d_api.h',
         'thunk/ppb_surface_3d_thunk.cc',
         'thunk/ppb_transport_api.h',
         'thunk/ppb_transport_thunk.cc',
         'thunk/ppb_url_loader_api.h',
         'thunk/ppb_url_loader_thunk.cc',
         'thunk/ppb_url_request_info_api.h',
         'thunk/ppb_url_request_info_thunk.cc',
         'thunk/ppb_url_response_info_api.h',
         'thunk/ppb_url_response_info_thunk.cc',
         'thunk/ppb_video_decoder_api.h',
         'thunk/ppb_video_decoder_thunk.cc',
         'thunk/ppb_video_layer_api.h',
         'thunk/ppb_video_layer_thunk.cc',
         'thunk/ppb_widget_api.h',
         'thunk/ppb_widget_thunk.cc',
         'thunk/ppb_zoom_thunk.cc',
         'thunk/thunk.h',
       ],
     },
   ],
 }