Add missing IWYU message_loop.h includes.

components/search_provider_logos/logo_tracker_unittest.cc

 // 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.
 
 #include "components/search_provider_logos/logo_tracker.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/base64.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/json/json_writer.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/simple_test_clock.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "components/search_provider_logos/google_logo_api.h"
 #include "net/base/url_util.h"
 #include "net/http/http_response_headers.h"
@@ skipping 723 matching lines @@
   MockLogoObserver listener2;
   listener2.ExpectFreshLogo(&logo);
   logo_tracker_->GetLogo(&listener2);
 
   base::RunLoop().RunUntilIdle();
 }
 
 }  // namespace
 
 }  // namespace search_provider_logos