use variadic macros/templates in IPC message implementation

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 12 matching lines @@
           'attachment_broker_unprivileged.cc',
           'attachment_broker_unprivileged.h',
           'attachment_broker_unprivileged_mac.cc',
           'attachment_broker_unprivileged_mac.h',
           'attachment_broker_unprivileged_win.cc',
           'attachment_broker_unprivileged_win.h',
           'brokerable_attachment.cc',
           'brokerable_attachment.h',
           'brokerable_attachment_mac.cc',
           'brokerable_attachment_win.cc',
+          'export_template.h',
           'handle_attachment_win.cc',
           'handle_attachment_win.h',
           'handle_win.cc',
           'handle_win.h',
           'ipc_channel.cc',
           'ipc_channel.h',
           'ipc_channel_factory.cc',
           'ipc_channel_factory.h',
           'ipc_channel_common.cc',
           'ipc_channel_handle.h',
@@ skipping 19 matching lines @@
           'ipc_message.cc',
           'ipc_message.h',
           'ipc_message_attachment.cc',
           'ipc_message_attachment.h',
           'ipc_message_attachment_set.cc',
           'ipc_message_attachment_set.h',
           'ipc_message_generator.cc',
           'ipc_message_generator.h',
           'ipc_message_macros.h',
           'ipc_message_start.h',
+          'ipc_message_templates.h',
+          'ipc_message_templates_impl.h',
           'ipc_message_utils.cc',
           'ipc_message_utils.h',
           'ipc_param_traits.h',
           'ipc_platform_file.cc',
           'ipc_platform_file.h',
           'ipc_platform_file_attachment_posix.cc',
           'ipc_platform_file_attachment_posix.h',
           'ipc_sender.h',
           'ipc_switches.cc',
           'ipc_switches.h',
@@ skipping 39 matching lines @@
           ['OS == "win" or OS == "ios"', {
             'sources!': [
               'unix_domain_socket_util.cc',
             ],
           }],
         ],
       }],
     ],
   },
 }