Move TransientDeviceId from MediFileSystemRegistry to RemovableStorageNotifications.

chrome/browser/media_gallery/transient_device_ids.cc

-// 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.
-
-// TransientDeviceIds implementation.
-
-#include "chrome/browser/media_gallery/transient_device_ids.h"
-
-#include "base/logging.h"
-#include "chrome/browser/system_monitor/media_storage_util.h"
-
-namespace chrome {
-
-TransientDeviceIds::TransientDeviceIds() : next_transient_id_(1) {}
-
-TransientDeviceIds::~TransientDeviceIds() {}
-
-uint64 TransientDeviceIds::GetTransientIdForDeviceId(
-    const std::string& device_id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(MediaStorageUtil::IsRemovableDevice(device_id));
-
-  bool inserted =
-      id_map_.insert(std::make_pair(device_id, next_transient_id_)).second;
-  if (inserted) {
-    // Inserted a device that has never been seen before.
-    ++next_transient_id_;
-  }
-  return id_map_[device_id];
-}
-
-}  // namespace chrome