Add language and keyboard layout pickers to public session pods

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 4828 matching lines @@
   </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>
+  <message name="IDS_LOGIN_PUBLIC_SESSION_LANGUAGE_AND_INPUT" desc="Link in public session pod that shows a section which allows the user to change the UI language and keyboard layout.">
+    Language and input
+  </message>
   <message name="IDS_LOGIN_PUBLIC_ACCOUNT_ENTER" meaning="Label text for signing in." desc="Label text for the sign-in button in the public account user pod.">
     Enter
   </message>
   <message name="IDS_LOGIN_PUBLIC_ACCOUNT_ENTER_ACCESSIBLE_NAME" desc="Text to be spoken when focus is set to the sign-in button in the public account user pod.">
     Enter public session
   </message>
   <message name="IDS_LOGIN_CONFIRM_KIOSK_DIAGNOSTIC_FORMAT" desc="Text to be shown on a dialog to confirm launching kiosk app in diagnostic mode.">
     Are you sure you want to launch "<ph name="APP_NAME">$1<ex>Kiosk App</ex></ph>" in diagnostic mode?
   </message>
   <message name="IDS_LOGIN_GUEST_SIGNIN_FIX_NETWORK">
@@ skipping 698 matching lines @@
   </message>
 
   <!-- 'OK Google' voice search activation display strings -->
   <message name="IDS_FLAGS_OK_GOOGLE_NAME" desc="Name of about:flags option for Ok Google.">
     Enable 'Ok Google' to activate voice search.
   </message>
   <message name="IDS_FLAGS_OK_GOOGLE_DESCRIPTION" desc="Description of about:flags option Ok Google.">
     If enabled, there will be an option in chrome:settings to enable saying 'Ok Google' to activate voice search.
   </message>
 </grit-part>