Add palette tray to ash.

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"
       output_all_resource_defines="false" source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/ash_strings.h" type="rc_header">
@@ skipping 345 matching lines @@
       </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
       </message>
 
+      <message name="IDS_ASH_PALETTE_TITLE" desc="The title of the palette in the ash shelf.">
+        Palette
+      </message>
+
       <message name="IDS_ASH_TOAST_DISMISS_BUTTON" desc="The text button shown in toasts to close the toast immediately without waiting timeout.">
         DISMISS
       </message>
 
       <message name="IDS_ASH_NOTIFICATION_UNREAD_COUNT_NINE_PLUS" desc="The text shown in the notification icon for the unread count when the count is more than 9.">
         9+
       </message>
       <message name="IDS_ASH_INTERNAL_DISPLAY_NAME" desc="The name used for internal displays, which is shown in the display settings.">
         Internal Display
       </message>
@@ skipping 36 matching lines @@
 
       <!-- ChromeOS-specific strings -->
       <if expr="chromeos">
         <part file="ash_chromeos_strings.grdp" />
       </if>
 
     </messages>
   </release>
 </grit>