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

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <message name="IDS_CHROMEBOOK" desc="The localized name for Chromebook.">
     Chromebook
   </message>
   <message name="IDS_CHROMEBOX" desc="The localized name for Chromebox">
@@ skipping 5014 matching lines @@
   <message name="IDS_LANGUAGES_MORE" desc="Main language list 'more' link. Expands all possible languages, not only the main ones.">
     More...
   </message>
   <message name="IDS_LOGIN_POD_OWNER_USER" desc="Login screen user pod menu title for a user who owns the device.">
     <ph name="USER_NAME">$1<ex>Ivan Arbuzov</ex></ph> (owner)
   </message>
   <message name="IDS_LOGIN_POD_REMOVE_USER" desc="Login screen user pod menu item text.">
     Remove this user
   </message>
   <message name="IDS_LOGIN_VERSION_LABEL_FORMAT" desc="Login screen version text format.">
-    <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> <ph name="PRODUCT_VERSION">$2<ex>15.0.0.0</ex></ph> (Platform <ph name="PLATFORM_VERSION">$3<ex>900.0-11.09.01</ex></ph>)
+    <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> <ph name="PRODUCT_VERSION">$2<ex>15.0.0.0</ex></ph> (Platform <ph name="PLATFORM_VERSION">$3<ex>900.0-11.09.01</ex></ph>) <ph name="DEVICE_SERIAL_NUMBER">$4<ex>SN:123456789ABC</ex></ph>
   </message>
   <message name="IDS_DEVICE_OWNED_BY_NOTICE" desc="Text for notifications showing that this is managed device.">
     This device is managed by <ph name="DOMAIN">$1<ex>acmecorp.com</ex></ph>.
   </message>
   <message name="IDS_LOGIN_PUBLIC_ACCOUNT_INFO_FORMAT" desc="Template for text shown in the public account user pod, informing the user that this is a public, managed account.">
     Managed by <ph name="DOMAIN">$1<ex>yourdomain.com</ex></ph>
   </message>
   <message name="IDS_LOGIN_PUBLIC_ACCOUNT_SIGNOUT_REMINDER" desc="Text shown in the public account user pod, reminding the user to log out.">
     Your information will be removed when you sign out.
   </message>
@@ skipping 778 matching lines @@
   <message name="IDS_SET_TIME_BUTTON_CLOSE" desc="Text for the button to close the window.">
     Done
   </message>
   <message name="IDS_SET_TIME_DATE_LABEL" desc="Label for the date input element.">
     System date
   </message>
   <message name="IDS_SET_TIME_TIME_LABEL" desc="Label for the time input element.">
     System time
   </message>
 </grit-part>