Use a direct include of the message_loop header in chrome/browser/, part 7.

chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac_unittest.mm

 // 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.
 
 #import <Foundation/Foundation.h>
 #import <ImageCaptureCore/ImageCaptureCore.h>
 
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/mac/cocoa_protocols.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/test/sequenced_worker_pool_owner.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/media_galleries/mac/mtp_device_delegate_impl_mac.h"
 #include "chrome/browser/storage_monitor/image_capture_device_manager.h"
 #include "chrome/browser/storage_monitor/test_storage_monitor.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_browser_thread.h"
@@ skipping 538 matching lines @@
                          temp_dir_.path().Append("target")));
 
   EXPECT_EQ(base::PLATFORM_FILE_OK,
              DownloadFile(base::FilePath("/ic:id/filename"),
                           temp_dir_.path().Append("target")));
   std::string contents;
   EXPECT_TRUE(file_util::ReadFileToString(temp_dir_.path().Append("target"),
                                           &contents));
   EXPECT_EQ(kTestFileContents, contents);
 }