Show a spinner UI for zero-touch enrollment

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>
   <!-- Idle logout dialog for retail mode -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog. Used in retail mode only.">
     Are you still there?
   </message>
@@ skipping 1545 matching lines @@
   </message>
   <message name="IDS_SIGNIN_SCREEN_TITLE" desc="Title of OOBE/Add User sign-in screen">
     Sign in
   </message>
   <message name="IDS_SIGNIN_SCREEN_TITLE_TAB_PROMPT" desc="Title of OOBE/Add User sign-in screen with TAB prompt when ChromeVox is active">
     Sign in, press the tab key to interact with input elements
   </message>
   <message name="IDS_LOGIN_GAIA_LOADING_MESSAGE" desc="Message on the OOBE gaia loading screen">
     Please wait...
   </message>
+  <message name="IDS_ENTERPRISE_ENROLLMENT_WORKING_MESSAGE" desc="Message to show while enrollment is in progress">
+    Please wait...
+  </message>
   <message name="IDS_NETWORK_SELECTION_TITLE" desc="Welcome title shown on network selection screen">
     Let's get started
   </message>
   <message name="IDS_OOBE_LANGUAGE_SELECTION_MSG" desc="Chrome OS OOBE: label for language selection dropdown">
     What is your language?
   </message>
   <message name="IDS_OOBE_ASSET_ID_LABEL" desc="Chrome OS OOBE: label for asset identifier.">
     Asset ID: <ph name="ASSET_ID">$1<ex>None specified</ex></ph>
   </message>
   <message name="IDS_NETWORK_SELECTION_SELECT" desc="Label for network selection dropdown">
@@ skipping 4759 matching lines @@
   <message name="IDS_FLAGS_ENABLE_EHV_INPUT_NAME" desc="Name of the about: flag for enabling emoji, handwriting and voice input on opt-in IME menu.">
     Emoji, handwriting and voice input on opt-in IME menu
     </message>
   <message name="IDS_FLAGS_ENABLE_EHV_INPUT_DESCRIPTION" desc="Description of the about: flag enabling emoji, handwriting and voice input on opt-in IME menu.">
     Enable access to emoji, handwriting and voice input form opt-in IME menu.
   </message>
   <message name="IDS_HATS_DONE_BUTTON_LABEL" desc="Label used for the done button at the end of survey">
     Done
   </message>
 </grit-part>