use variadic macros/templates in IPC message implementation

base/BUILD.gn

 # Copyright (c) 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.
 
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/config/ui.gni")
 import("//build/nocompile.gni")
 import("//testing/test.gni")
 
@@ skipping 188 matching lines @@
     "containers/small_map.h",
     "containers/stack_container.h",
     "cpu.cc",
     "cpu.h",
     "critical_closure.h",
     "critical_closure_internal_ios.mm",
     "deferred_sequenced_task_runner.cc",
     "deferred_sequenced_task_runner.h",
     "environment.cc",
     "environment.h",
+    "export_template.h",
     "feature_list.cc",
     "feature_list.h",
     "file_descriptor_posix.h",
     "file_version_info.h",
     "file_version_info_mac.h",
     "file_version_info_mac.mm",
     "file_version_info_win.cc",
     "file_version_info_win.h",
     "files/dir_reader_fallback.h",
     "files/dir_reader_linux.h",
@@ skipping 1552 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }