[PPAPI] Implement an IOStreamResource for data transmission between plugin and renderer.

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': [
       # This part is shared between the targets defined below.
       ['ppapi_shared_target==1', {
         'sources': [
           'shared_impl/array_var.cc',
           'shared_impl/array_var.h',
           'shared_impl/array_writer.cc',
           'shared_impl/array_writer.h',
           'shared_impl/callback_tracker.cc',
           'shared_impl/callback_tracker.h',
+          'shared_impl/circular_buffer.cc',
+          'shared_impl/circular_buffer.h',
           'shared_impl/dictionary_var.cc',
           'shared_impl/dictionary_var.h',
           'shared_impl/file_io_state_manager.cc',
           'shared_impl/file_io_state_manager.h',
           'shared_impl/file_path.cc',
           'shared_impl/file_path.h',
           'shared_impl/file_ref_create_info.cc',
           'shared_impl/file_ref_create_info.h',
           'shared_impl/file_ref_util.cc',
           'shared_impl/file_ref_util.h',
           'shared_impl/file_system_util.cc',
           'shared_impl/file_system_util.h',
           'shared_impl/file_type_conversion.cc',
           'shared_impl/file_type_conversion.h',
           'shared_impl/flash_clipboard_format_registry.cc',
           'shared_impl/flash_clipboard_format_registry.h',
           'shared_impl/host_resource.cc',
           'shared_impl/host_resource.h',
           'shared_impl/id_assignment.cc',
           'shared_impl/id_assignment.h',
+          'shared_impl/io_stream_shared.cc',
+          'shared_impl/io_stream_shared.h',
           'shared_impl/platform_file.cc',
           'shared_impl/platform_file.h',
           'shared_impl/ppapi_globals.cc',
           'shared_impl/ppapi_globals.h',
           'shared_impl/ppapi_nacl_channel_args.cc',
           'shared_impl/ppapi_nacl_channel_args.h',
           'shared_impl/ppapi_permissions.cc',
           'shared_impl/ppapi_permissions.h',
           'shared_impl/ppapi_preferences.cc',
           'shared_impl/ppapi_preferences.h',
@@ skipping 283 matching lines @@
               'thunk/ppb_tcp_socket_private_thunk.cc',
               'thunk/ppb_udp_socket_private_thunk.cc',
               'thunk/ppb_x509_certificate_private_thunk.cc',
             ],
           }],
         ],
       }],
     ],
   },
 }