Use the machine hostname on Linux machines for the sync session name rather than

sync/util/get_session_name_linux.h

+// Copyright (c) 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.
+
+#ifndef SYNC_UTIL_GET_SESSION_NAME_LINUX_H_
+#define SYNC_UTIL_GET_SESSION_NAME_LINUX_H_
+
+#include <string>
+
+namespace syncer {
+namespace internal {
+
+std::string GetHostname();
+
+}  // namespace internal
+}  // namespace syncer
+
+#endif  // SYNC_UTIL_GET_SESSION_NAME_LINUX_H_
+