[Sync] Simplify GetSessionName interface

chrome/browser/sync/util/get_session_name.h

+// 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.
+
+#ifndef CHROME_BROWSER_SYNC_UTIL_GET_SESSION_NAME_H_
+#define CHROME_BROWSER_SYNC_UTIL_GET_SESSION_NAME_H_
+#pragma once
+
+#include <string>
+
+#include "base/callback_forward.h"
+#include "base/memory/ref_counted.h"
+#include "base/task_runner.h"
+#include "build/build_config.h"
+
+namespace browser_sync {
+
+namespace internal {
+#if defined(OS_MACOSX)
+// Returns the Hardware model name, without trailing numbers, if
+// possible.  See http://www.cocoadev.com/index.pl?MacintoshModels for
+// an example list of models. If an error occurs trying to read the
+// model, this simply returns "Unknown".
+std::string GetHardwareModelName();
+#endif
+
+#if defined(OS_WIN)
+// Returns the computer name or the empty string if an error occured.
+std::string GetComputerName();
+#endif
+}  // namespace internal
+
+void GetSessionName(
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Callback<void(const std::string&)>& done_callback);
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_UTIL_GET_SESSION_NAME_H_