Add missing IWYU message_loop.h includes.

storage/browser/fileapi/obfuscated_file_util_unittest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 
 #include <limits>
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "storage/browser/fileapi/external_mount_points.h"
 #include "storage/browser/fileapi/file_system_backend.h"
 #include "storage/browser/fileapi/file_system_context.h"
 #include "storage/browser/fileapi/file_system_operation_context.h"
 #include "storage/browser/fileapi/file_system_usage_cache.h"
 #include "storage/browser/fileapi/obfuscated_file_util.h"
 #include "storage/browser/fileapi/sandbox_directory_database.h"
@@ skipping 2543 matching lines @@
   ofu()->GetDirectoryForOriginAndType(
       origin2, GetTypeString(kFileSystemTypeTemporary), false, &error);
   ASSERT_EQ(base::File::FILE_OK, error);
   error = base::File::FILE_ERROR_FAILED;
   ofu()->GetDirectoryForOriginAndType(
       origin2, GetTypeString(kFileSystemTypePersistent), false, &error);
   ASSERT_EQ(base::File::FILE_OK, error);
 }
 
 }  // namespace content