[mojo-edk] Add explicit message object APIs

mojo/edk/system/BUILD.gn

 # Copyright 2014 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("//testing/test.gni")
 import("../../../mojo/public/tools/bindings/mojom.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ skipping 34 matching lines @@
     "data_pipe_control_message.h",
     "data_pipe_producer_dispatcher.cc",
     "data_pipe_producer_dispatcher.h",
     "dispatcher.cc",
     "dispatcher.h",
     "handle_signals_state.h",
     "handle_table.cc",
     "handle_table.h",
     "mapping_table.cc",
     "mapping_table.h",
+    "message_for_transit.cc",
+    "message_for_transit.h",
     "message_pipe_dispatcher.cc",
     "message_pipe_dispatcher.h",
     "node_channel.cc",
     "node_channel.h",
     "node_controller.cc",
     "node_controller.h",
     "options_validation.h",
     "platform_handle_dispatcher.cc",
     "platform_handle_dispatcher.h",
     "ports_message.cc",
@@ skipping 125 matching lines @@
   deps = [
     ":test_utils",
     "//base",
     "//base/test:test_support",
     "//mojo/edk/system",
     "//mojo/edk/test:run_all_perftests",
     "//mojo/edk/test:test_support",
     "//testing/gtest",
   ]
 }