Add API definition and error values for running message loops.

ppapi/ppapi_sources.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.
 
 {
   'variables': {
     'c_source_files': [
       'c/pp_bool.h',
       'c/pp_completion_callback.h',
       'c/pp_errors.h',
@@ skipping 44 matching lines @@
       'c/dev/ppb_char_set_dev.h',
       'c/dev/ppb_console_dev.h',
       'c/dev/ppb_cursor_control_dev.h',
       'c/dev/ppb_directory_reader_dev.h',
       'c/dev/ppb_file_chooser_dev.h',
       'c/dev/ppb_find_dev.h',
       'c/dev/ppb_font_dev.h',
       'c/dev/ppb_fullscreen_dev.h',
       'c/dev/ppb_ime_input_event_dev.h',
       'c/dev/ppb_memory_dev.h',
+      'c/dev/ppb_message_loop_dev.h',
       'c/dev/ppb_scrollbar_dev.h',
       'c/dev/ppb_testing_dev.h',
       'c/dev/ppb_url_util_dev.h',
       'c/dev/ppb_var_array_buffer_dev.h',
       'c/dev/ppb_video_decoder_dev.h',
       'c/dev/ppb_websocket_dev.h',
       'c/dev/ppb_widget_dev.h',
       'c/dev/ppb_zoom_dev.h',
       'c/dev/ppp_cursor_control_dev.h',
       'c/dev/ppp_find_dev.h',
@@ skipping 313 matching lines @@
           'c/dev/ppb_transport_dev.h',
         ],
         'cpp_source_files': [
           'cpp/dev/transport_dev.cc',
           'cpp/dev/transport_dev.h',
         ],
       },
     }],
   ],
 }