Show the serial number of the device in the version string if available.

chrome/browser/chromeos/login/version_info_updater.h

Index: chrome/browser/chromeos/login/version_info_updater.h
diff --git a/chrome/browser/chromeos/login/version_info_updater.h b/chrome/browser/chromeos/login/version_info_updater.h
index b8474e8485bd30403375c370930d7d17bcf8d60b..fb74fa73ca26f483d644958ed21a67c4cf39a427 100644
--- a/chrome/browser/chromeos/login/version_info_updater.h
+++ b/chrome/browser/chromeos/login/version_info_updater.h
@@ -59,6 +59,9 @@ class VersionInfoUpdater : public policy::CloudPolicyStore::Observer {
   // Set enterprise domain name.
   void SetEnterpriseInfo(const std::string& domain_name);
 
+  // Creates a serial number string.
+  void UpdateSerialNumberInfo();
+
   // Callback from chromeos::VersionLoader giving the version.
   void OnVersion(const std::string& version);
 
@@ -71,6 +74,7 @@ class VersionInfoUpdater : public policy::CloudPolicyStore::Observer {
 
   // Information pieces for version label.
   std::string version_text_;
+  std::string serial_number_text_;
 
   // Full text for the OS version label.
   std::string os_version_label_text_;