ash: Remove OS_CHROMEOS ifdefs from accelerator files

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 369 matching lines @@
         Magnifying glass mode
       </message>
       <message name="IDS_ASH_STYLUS_TOOLS_TITLE" desc="The title of the stylus tools dialog in the ash shelf.">
         Stylus tools
       </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_EXIT_WARNING_POPUP_TEXT" desc="The text of the popup when the user preses the exit shortcut.">
-        Press Ctrl+Shift+Q twice to quit.
-      </message>
-      <message name="IDS_ASH_EXIT_WARNING_POPUP_TEXT_ACCESSIBLE" desc="The message used by accessibility to indicate the content of the popup when the user preses the exit shortcut.">
-        Press Control Shift Q twice to quit.
-      </message>
-
       <message name="IDS_ASH_CONTROL_KEY" desc="Name of [Ctrl] key name. Shouldn't be translated in many languages actually. This name should be lower case.">
         ctrl
       </message>
       <message name="IDS_ASH_SHIFT_KEY" desc="Name of [Shift] key. Shouldn't be translated in many languages actually. This name should be lower case.">
         shift
       </message>
       <message name="IDS_ASH_ALT_KEY" desc="Name of [Alt] key name. Shouldn't be translated in many languages actually. This name should be lower case.">
         alt
       </message>
       <message name="IDS_ASH_SEARCH_KEY" desc="Name of [Search] key name. This name should be lower case.">
@@ skipping 13 matching lines @@
 
       <!-- ChromeOS-specific strings -->
       <if expr="chromeos">
         <part file="ash_chromeos_strings.grdp" />
       </if>
 
     </messages>
   </release>
 </grit>