[Sync] Removing duplicate includes, part 2.

components/sync/core_impl/attachments/attachment_store_frontend_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/sync/core/attachments/attachment_store_frontend.h"
 
-#include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/sync/api/attachments/attachment.h"
 #include "components/sync/api/attachments/attachment_id.h"
 #include "components/sync/api/attachments/attachment_store_backend.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace syncer {
 
@@ skipping 207 matching lines @@
 
   // Releasing referehce to AttachmentStoreFrontend should result in
   // MockAttachmentStore being deleted on backend loop.
   attachment_store_frontend_ = NULL;
   EXPECT_EQ(dtor_call_count_, 0);
   RunMessageLoop();
   EXPECT_EQ(dtor_call_count_, 1);
 }
 
 }  // namespace syncer