First pass at implementing the MessageLoop interface. This includes a simple

ppapi/ppapi_shared.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'ppapi_shared',
       'type': '<(component)',
       'dependencies': [
@@ skipping 154 matching lines @@
         'thunk/ppb_graphics_3d_api.h',
         'thunk/ppb_graphics_3d_thunk.cc',
         'thunk/ppb_graphics_3d_trusted_thunk.cc',
         'thunk/ppb_image_data_api.h',
         '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_message_loop_api.h',
         'thunk/ppb_messaging_thunk.cc',
         'thunk/ppb_mouse_lock_thunk.cc',
         'thunk/ppb_pdf_api.h',
         'thunk/ppb_resource_array_api.h',
         'thunk/ppb_resource_array_thunk.cc',
         'thunk/ppb_scrollbar_api.h',
         'thunk/ppb_scrollbar_thunk.cc',
         'thunk/ppb_tcp_socket_private_api.h',
         'thunk/ppb_tcp_socket_private_thunk.cc',
         'thunk/ppb_text_input_api.h',
@@ skipping 20 matching lines @@
         'thunk/ppb_websocket_api.h',
         'thunk/ppb_websocket_thunk.cc',
         'thunk/ppb_widget_api.h',
         'thunk/ppb_widget_thunk.cc',
         'thunk/ppb_zoom_thunk.cc',
         'thunk/thunk.h',
       ],
     },
   ],
 }