Add missing IWYU message_loop.h includes.

rlz/lib/rlz_lib_test.cc

 // 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.
 //
 // A test application for the RLZ library.
 //
 // These tests should not be executed on the build server:
 // - They assert for the failed cases.
 // - They modify machine state (registry).
 //
 // These tests require write access to HKLM and HKCU.
 //
 // The "GGLA" brand is used to test the normal code flow of the code, and the
 // "TEST" brand is used to test the supplementary brand code code flow.
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/single_thread_task_runner.h"
 #include "build/build_config.h"
-#include "testing/gmock/include/gmock/gmock.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
 #include "rlz/lib/financial_ping.h"
 #include "rlz/lib/net_response_check.h"
 #include "rlz/lib/rlz_lib.h"
 #include "rlz/lib/rlz_value_store.h"
 #include "rlz/test/rlz_test_helpers.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_WIN)
 #include <Windows.h>
 #include "rlz/win/lib/machine_deal.h"
 #endif
 
 #if defined(RLZ_NETWORK_IMPLEMENTATION_CHROME_NET)
 #include "base/mac/scoped_nsautorelease_pool.h"
 #include "base/threading/thread.h"
 #include "net/url_request/url_request_test_util.h"
@@ skipping 893 matching lines @@
   int mkdir_result = mkdir(rlz_lib::testing::RlzStoreFilenameStr().c_str(),
                            0500);
   ASSERT_EQ(0, mkdir_result);
 
   rlz_lib::SupplementaryBranding branding("TEST");
   EXPECT_FALSE(rlz_lib::RecordProductEvent(rlz_lib::TOOLBAR_NOTIFIER,
       rlz_lib::IE_DEFAULT_SEARCH, rlz_lib::INSTALL));
 }
 
 #endif