drive: Add "Delta Update Status" section to chrome:drive-internals

chrome/browser/chromeos/drive/drive_file_system_metadata.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.
+
+#include "chrome/browser/chromeos/drive/drive_file_system_metadata.h"
+
+namespace drive {
+
+DriveFileSystemMetadata::DriveFileSystemMetadata()
+    : largest_changestamp(0),
+      push_notification_enabled(false),
+      polling_interval_sec(0),
+      last_update_check_error(DRIVE_FILE_OK) {
+}
+
+DriveFileSystemMetadata::~DriveFileSystemMetadata() {
+}
+
+}  // namespace drive