PPAPI: Implement PPB_FileMapping on POSIX

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.
 
 {
   'target_defaults': {
     'variables': {
       'ppapi_shared_target': 0,
     },
     'target_conditions': [
@@ skipping 145 matching lines @@
           'thunk/ppb_device_ref_api.h',
           'thunk/ppb_device_ref_dev_thunk.cc',
           'thunk/ppb_ext_crx_file_system_private_thunk.cc',
           'thunk/ppb_ext_socket_thunk.cc',
           'thunk/ppb_file_chooser_api.h',
           'thunk/ppb_file_chooser_dev_thunk.cc',
           'thunk/ppb_file_chooser_trusted_thunk.cc',
           'thunk/ppb_file_io_api.h',
           'thunk/ppb_file_io_private_thunk.cc',
           'thunk/ppb_file_io_thunk.cc',
+          'thunk/ppb_file_mapping_thunk.cc',
           'thunk/ppb_file_ref_api.h',
           'thunk/ppb_file_ref_thunk.cc',
           'thunk/ppb_file_system_api.h',
           'thunk/ppb_file_system_thunk.cc',
           'thunk/ppb_find_dev_thunk.cc',
           'thunk/ppb_flash_clipboard_api.h',
           'thunk/ppb_flash_clipboard_thunk.cc',
           'thunk/ppb_flash_device_id_thunk.cc',
           'thunk/ppb_flash_drm_api.h',
           'thunk/ppb_flash_drm_thunk.cc',
@@ skipping 168 matching lines @@
               'thunk/ppb_tcp_socket_private_thunk.cc',
               'thunk/ppb_udp_socket_private_thunk.cc',
               'thunk/ppb_x509_certificate_private_thunk.cc',
             ],
           }],
         ],
       }],
     ],
   },
 }