Add missing IWYU message_loop.h includes.

chrome/browser/conflicts/module_inspector_win_unittest.cc

 // Copyright 2017 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.
 
 #include "chrome/browser/conflicts/module_inspector_win.h"
 
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/environment.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/test/scoped_task_scheduler.h"
 #include "base/test/test_simple_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 base::FilePath GetKernel32DllFilePath() {
   std::unique_ptr<base::Environment> env = base::Environment::Create();
   std::string sysroot;
@@ skipping 62 matching lines @@
       {base::FilePath(), 0, 0, 4},
       {base::FilePath(), 0, 0, 5},
   });
 
   base::RunLoop().RunUntilIdle();
 
   EXPECT_EQ(5u, inspected_modules().size());
   for (const auto& inspection_result : inspected_modules())
     EXPECT_TRUE(inspection_result);
 }