FileManagerBrowserTest: removed unused includes

Remove unused #include. Also update to copyright notice per style.

Bug: 836254
Change-Id: Icb7bcec55d20535cdd2f0f5eb49bd1c3e22ca2ca
Reviewed-on: https://chromium-review.googlesource.com/1056747Reviewed-by: Stuart Langley <slangley@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558166}

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright 2018 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.
 
@@ -6,8 +6,6 @@
 
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/threading/thread_restrictions.h"
-#include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/file_manager/file_manager_browsertest_base.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/signin/identity_manager_factory.h"