Show "Update Chrome OS" in the wrench menu, when the update image is ready.

chrome/app/generated_resources.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- This file contains definitions of resources that will be translated for
 each locale. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/generated_resources.h" type="rc_header">
       <emit emit_type='prepend'></emit>
@@ skipping 8614 matching lines @@
     <message name="IDS_PROFILE_IN_USE_LINUX" desc="Message shown when the browser cannot start because the profile is in use on a different host.">
       The profile appears to be in use by process <ph name="PROCESS_ID">$1<ex>12345</ex></ph> on host <ph name="HOST_NAME">$2<ex>example.com</ex></ph>.  If you are sure no other processes are using this profile, delete the file <ph name="LOCK_FILE">$3<ex>/home/user/.config/google-chrome/SingletonLock</ex></ph> and restart <ph name="PRODUCT_NAME">$4<ex>Google Chrome</ex></ph>.
     </message>
 
     <!-- Theme UI -->
     <message name="IDS_THEME_LOADING_TITLE" desc="The text to be displayed in a window while a theme is loading.">
       Loading...
     </message>
 
     <!-- Update Recommended dialog -->
-    <message name="IDS_UPDATE_RECOMMENDED" desc="The main text of the Update Recommended dialog.">
-      <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> is out of date because it hasn't been restarted in a while. An update is available and will be applied as soon as you restart.
-    </message>
+    <if expr="not pp_ifdef('chromeos')">
+      <message name="IDS_UPDATE_RECOMMENDED" desc="The main text of the Update Recommended dialog.">
+        <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> is out of date because it hasn't been restarted in a while. An update is available and will be applied as soon as you restart.
+      </message>
+    </if>
+    <if expr="pp_ifdef('chromeos')">
+      <message name="IDS_UPDATE_RECOMMENDED" desc="The main text of the Update Recommended dialog.">
+        <ph name="PRODUCT_NAME">$1<ex>Google Chrome OS</ex></ph> needs to be restarted to apply the update.
+      </message>
+    </if>
     <message name="IDS_RESTART_AND_UPDATE" desc="The button label for restarting and updating Chrome.">
       Restart
     </message>
     <if expr="not pp_ifdef('use_titlecase')">
       <message name="IDS_NOT_NOW" desc="The button label for delaying the restart and updating Chrome.">
         Not now
       </message>
     </if>
     <if expr="pp_ifdef('use_titlecase')">
       <message name="IDS_NOT_NOW" desc="In Tile Case: The button label for delaying the restart and updating Chrome.">
@@ skipping 222 matching lines @@
       <message name="IDS_UPDATE_DOWNLOADING" desc="Notification for update download progress">
         System update downloading: <ph name="PERCENT">$1<ex>10</ex></ph>&#37; complete.
       </message>
       <message name="IDS_UPDATE_VERIFYING" desc="Notification for update verifying">
         Verifying system update&#x2026;
       </message>
       <message name="IDS_UPDATE_FINALIZING" desc="Notification for update finalizing">
         Finalizing system update&#x2026;
       </message>
       <message name="IDS_UPDATE_COMPLETED" desc="Notification for update completed">
-        System update complete. Please restart the system by pressing the power button, wait for the system to power down, then press the power button again.
+        System update complete. Please restart the system.
       </message>
       <message name="IDS_INSTALLING_UPDATE" desc="Label shown on the updates installation screen during OOBE">
         Please wait while <ph name="PRODUCT_NAME">$1<ex>Chrome OS</ex></ph> installs the latest system updates.
       </message>
       <message name="IDS_INSTALLING_UPDATE_DESC" desc="Additional info shown on the updates installation screen during OOBE">
         Your computer will restart when the update is complete.
       </message>
       <message name="IDS_NETWORK_SELECTION_TITLE" desc="Welcome title shown on network selection screen">
         Welcome to <ph name="PRODUCT_NAME">$1<ex>Chrome OS</ex></ph>
       </message>
@@ skipping 1762 matching lines @@
 
     </messages>
 
     <structures fallback_to_english="true">
       <structure name="IDD_CHROME_FRAME_FIND_DIALOG" file="cf_resources.rc" type="dialog" >
       </structure>
     </structures>
 
   </release>
 </grit>