Added prefs ui for enabling/disabling background mode on windows.

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 5570 matching lines @@
       <message name="IDS_OFF_THE_RECORD_TOOLTIP" desc="The tooltip for the incognito icon.">
         You have opened an incognito window. Pages that you open in this window won't appear in your history.
       </message>
 
       <!-- Default Browser related messages -->
       <message name="IDS_HIDE_ICONS_NOT_SUPPORTED" desc="Message to explain we only support uninstall and not hide-icons.">
         To hide access to this program, you need to uninstall it by using\n<ph name="CONTROL_PANEL_APPLET_NAME">$1<ex>Add/Remove Programs</ex></ph> in Control Panel.\n\nWould you like to start <ph name="CONTROL_PANEL_APPLET_NAME">$1<ex>Add/Remove Programs</ex></ph>?
       </message>
 
       <!-- Options Window -->
+      <message name="IDS_OPTIONS_CHROME_APPS_ENABLE_BACKGROUND_MODE" desc="The label in the checkbox that enables background mode for installed web apps.">
+        Allow installed web apps to run in the background and launch on system start
+      </message>
       <message name="IDS_OPTIONS_DIALOG_TITLE" desc="The title of the Options dialog box">
         <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> Options
       </message>
       <if expr="pp_ifdef('chromeos')">
         <message name="IDS_OPTIONS_SYSTEM_TAB_LABEL" desc="The title of the System tab">
           System
         </message>
         <message name="IDS_OPTIONS_INTERNET_TAB_LABEL" desc="The title of the Internet tab">
           Internet
         </message>
@@ skipping 3633 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>