ipc: Make a common subclass for Channel and ProxyChannel.

ipc/ipc.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': {
       'ipc_target': 0,
     },
     'target_conditions': [
@@ skipping 25 matching lines @@
           'ipc_channel_nacl.h',
           'ipc_channel_posix.cc',
           'ipc_channel_posix.h',
           'ipc_channel_proxy.cc',
           'ipc_channel_proxy.h',
           'ipc_channel_reader.cc',
           'ipc_channel_reader.h',
           'ipc_channel_win.cc',
           'ipc_channel_win.h',
           'ipc_descriptors.h',
+          'ipc_endpoint.cc',
+          'ipc_endpoint.h',
           'ipc_export.h',
           'ipc_handle_win.cc',
           'ipc_handle_win.h',
           'ipc_listener.h',
           'ipc_logging.cc',
           'ipc_logging.h',
           'ipc_message.cc',
           'ipc_message.h',
           'ipc_message_attachment.cc',
           'ipc_message_attachment.h',
@@ skipping 49 matching lines @@
           ['OS == "win" or OS == "ios"', {
             'sources!': [
               'unix_domain_socket_util.cc',
             ],
           }],
         ],
       }],
     ],
   },
 }