Add help button to app launcher

ui/base/strings/ui_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!-- This file contains definitions of resources that will be translated for
 each locale. Specifically, these are UI strings that are used by app/ that
 need to be translated for each locale.-->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <!-- TODO add each of your output files.  Modify the three below, and add
@@ skipping 454 matching lines @@
         <ph name="product">$1<ex>Chrome</ex></ph> - Notifications
       </message>
       <message name="IDS_MESSAGE_CENTER_TOOLTIP_UNREAD" desc="Tooltip for notification tray icon with unread notifications">
         <ph name="product">$1<ex>Chrome</ex></ph> - Notifications (<ph name="QUANTITY">$2<ex>3</ex></ph> unread)
       </message>
 
       <!-- App list -->
       <message name="IDS_APP_LIST_OPEN_SETTINGS" desc="The menu entry to show the settings UI.">
         Settings
       </message>
+      <message name="IDS_APP_LIST_HELP" desc="The menu entry to show the app list help UI.">

[sky, 2013/04/10 14:09:58]

Try to keep sorted, so move this above IDS_APP_LIST_OPEN_SETTINGS

[calamity, 2013/05/27 07:47:24]

Done.

+        Help
+      </message>
       <message name="IDS_APP_LIST_OPEN_FEEDBACK" desc="The menu entry to show the feedback UI.">
         Send feedback
       </message>
     </messages>
   </release>
 </grit>