Create new class "CastTransport", which encapsulates the message read and write event loops.

extensions/extensions.gyp

 # Copyright 2013 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': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 323 matching lines @@
         'browser/api/bluetooth_socket/bluetooth_socket_api.cc',
         'browser/api/bluetooth_socket/bluetooth_socket_api.h',
         'browser/api/bluetooth_socket/bluetooth_socket_event_dispatcher.cc',
         'browser/api/bluetooth_socket/bluetooth_socket_event_dispatcher.h',
         'browser/api/capture_web_contents_function.h',
         'browser/api/capture_web_contents_function_impl.h',
         'browser/api/cast_channel/cast_auth_util.cc',
         'browser/api/cast_channel/cast_auth_util.h',
         'browser/api/cast_channel/cast_channel_api.cc',
         'browser/api/cast_channel/cast_channel_api.h',
+        'browser/api/cast_channel/cast_framer.cc',
+        'browser/api/cast_channel/cast_framer.h',
         'browser/api/cast_channel/cast_message_util.cc',
         'browser/api/cast_channel/cast_message_util.h',
         'browser/api/cast_channel/cast_socket.cc',
         'browser/api/cast_channel/cast_socket.h',
+        'browser/api/cast_channel/cast_framer.cc',
+        'browser/api/cast_channel/cast_framer.h',
+        'browser/api/cast_channel/cast_transport.h',
+        'browser/api/cast_channel/cast_transport.cc',
         'browser/api/cast_channel/logger.cc',
         'browser/api/cast_channel/logger.h',
         'browser/api/cast_channel/logger_util.cc',
         'browser/api/cast_channel/logger_util.h',
         'browser/api/declarative/deduping_factory.h',
         'browser/api/dns/dns_api.cc',
         'browser/api/dns/dns_api.h',
         'browser/api/dns/host_resolver_wrapper.cc',
         'browser/api/dns/host_resolver_wrapper.h',
         'browser/api/extensions_api_client.cc',
@@ skipping 687 matching lines @@
           'browser/api/cast_channel/logging.proto'
       ],
       'variables': {
           'proto_in_dir': 'browser/api/cast_channel',
           'proto_out_dir': 'extensions/browser/api/cast_channel',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ]
 }