Report Windows build and patch number in the component updater checks.

components/update_client/utils_win.h

+// Copyright 2016 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 COMPONENTS_UPDATE_CLIENT_UTILS_WIN_H_
+#define COMPONENTS_UPDATE_CLIENT_UTILS_WIN_H_
+
+#include <string>
+
+namespace update_client {
+
+// Returns a dotted quad Windows string representing the Windows OS version.
+// The format of the version string is major.minor.build-number.ubr.
+std::string GetWindowsOSVersion();
+
+}  // namespace update_client
+
+#endif  // COMPONENTS_UPDATE_CLIENT_UTILS_WIN_H_