Add device policy to disallow shutdown - ash UI modifications

ash/ash_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!--
 This file contains the strings for ash.
 -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/ash_strings.h" type="rc_header">
@@ skipping 334 matching lines @@
       </message>
       <message name="IDS_ASH_STATUS_TRAY_ACCESSIBILITY_SETTINGS" desc="The label of the item 'Settings...' used in the accessibility menu of the system tray to open an accessibility setting page.">
         Settings...
       </message>
       <message name="IDS_ASH_STATUS_TRAY_HELP" desc="The accessible text for the help button.">
         Help
       </message>
       <message name="IDS_ASH_STATUS_TRAY_DATE" desc="The date displayed on ash system bubble, Depending on launguage, please choose the best separator(eg ',') between abbreviated weekday and date">
         <ph name="short_weekday">$1<ex>Fri</ex></ph>, <ph name="date">$2<ex>Aug 31, 2012</ex></ph>
       </message>
+      <message name="IDS_ASH_STATUS_TRAY_REBOOT" desc="The accessible text for the reboot button.">

[Daniel Erat, 2015/01/07 16:18:40]

nit: "the restart button"?

i think it's a bit weird that we call it rebooting in the code and restarting in
the ui, but i don't know if it's worth changing. "restarting" is a bit vague
when reading the code but i can understand if we don't want to show users the
word "reboot".

[cschuet (SLOW), 2015/01/13 10:38:28]

Indeed, the rationale was that all user-facing strings mention "restart" rather
than "reboot".

+        Restart
+      </message>
       <message name="IDS_ASH_STATUS_TRAY_SHUTDOWN" desc="The accessible text for the shutdown button.">
         Shut down
       </message>
 
       <message name="IDS_ASH_STATUS_TRAY_SUPERVISED_LABEL" desc="Label shown instead of email for supervised users">
          Supervised user
       </message>
 
       <message name="IDS_ASH_STATUS_TRAY_PREVIOUS_MENU" desc="The accessible text for header entries for detailed versions of status tray items.">
         Previous menu
@@ skipping 53 matching lines @@
 
       <!-- ChromeOS-specific strings -->
       <if expr="chromeos">
         <part file="ash_chromeos_strings.grdp" />
       </if>
 
     </messages>
   </release>
 </grit>