[fsp] Introduce file_system_provider::Service class for the FileSystemProvider API.

chrome/browser/chromeos/file_system_provider/provided_file_system.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 "chrome/browser/chromeos/file_system_provider/provided_file_system.h"
+
+namespace chromeos {
+namespace file_system_provider {
+
+ProvidedFileSystem::ProvidedFileSystem() {}
+
+ProvidedFileSystem::ProvidedFileSystem(const std::string& extension_id,
+                                       const std::string& file_system_id,
+                                       const std::string& file_system_name,
+                                       const base::FilePath& mount_path)
+    : extension_id_(extension_id),
+      file_system_id_(file_system_id),
+      file_system_name_(file_system_name),
+      mount_path_(mount_path) {}
+
+ProvidedFileSystem::~ProvidedFileSystem() {}
+
+}  // namespace file_system_provider
+}  // namespace chromeos