Add missing IWYU message_loop.h includes.

chrome/browser/history/redirect_browsertest.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.
 
 // Navigates the browser to server and client redirect pages and makes sure
 // that the correct redirects are reflected in the history database. Errors
 // here might indicate that WebKit changed the calls our glue layer gets in
 // the case of redirects. It may also mean problems with the history system.
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/location.h"
+#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 280 matching lines @@
   // as a client redirect from the first (/client-redirect?) page.
   for (std::vector<GURL>::iterator it = redirects.begin();
        it != redirects.end(); ++it) {
     if (final_url.spec() == it->spec()) {
       final_navigation_not_redirect = false;
       break;
     }
   }
   EXPECT_TRUE(final_navigation_not_redirect);
 }