Add an extensions keep-alive client.

extensions/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("//tools/grit/grit_rule.gni")
 import("//tools/grit/repack.gni")
 
 # GYP version: extensions/extensions_resources.gyp:extensions_resources
 group("extensions_resources") {
   deps = [
@@ skipping 220 matching lines @@
     "renderer/api/serial/serial_api_unittest.cc",
     "renderer/api_test_base.cc",
     "renderer/api_test_base.h",
     "renderer/api_test_base_unittest.cc",
     "renderer/event_unittest.cc",
     "renderer/json_schema_unittest.cc",
     "renderer/messaging_utils_unittest.cc",
     "renderer/module_system_test.cc",
     "renderer/module_system_test.h",
     "renderer/module_system_unittest.cc",
+    "renderer/mojo/keep_alive_client_unittest.cc",
     "renderer/safe_builtins_unittest.cc",
     "renderer/script_context_set_unittest.cc",
     "renderer/utils_unittest.cc",
     "test/extensions_unittests_main.cc",
   ]
 
   deps = [
     ":extensions_resources",
     ":shell_and_test_pak",
     ":test_support",
@@ skipping 18 matching lines @@
 
   if (is_win) {
     deps += [
       "//base/allocator",
     ]
   }
 }
 }
 
 }