Add "Keep chrome running in background" preference.

chrome/app/chromium_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This file contains definitions of strings that are distribution specific.
 These strings will not be translated and only english versions will
 be available for now. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/chromium_strings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
@@ skipping 317 matching lines @@
       <if expr="not pp_ifdef('chromeos')">
         <message name="IDS_OPTIONS_RELAUNCH_REQUIRED" desc="The message displayed for an option that requires a relaunch to take effect. This appears in a message box if an option is changed that requires a relaunch.">
           Please close all Chromium windows and relaunch Chromium for this change to take effect.
         </message>
       </if>
       <if expr="pp_ifdef('chromeos')">
         <message name="IDS_OPTIONS_RELAUNCH_REQUIRED" desc="The message displayed for an option that requires a relaunch to take effect. This appears in a message box if an option is changed that requires a relaunch.">
           Please sign out of Chromium OS and sign in again for this change to take effect.
         </message>
       </if>
+      <message name="IDS_OPTIONS_BACKGROUND_ENABLE_BACKGROUND_MODE" desc="The label of the check-box that enables background mode">
+        Continue running background apps when Chromium is closed

[Rick Campbell, 2011/05/11 20:33:01]

I think that you should replace "Continue running background apps when Chromium
is closed" with "Keep Chromium running in the background after the last window
is closed."

This phrasing revives points from older discussions, specifically (a) Chrome is
running, not just those apps and (b) "Chromium is closed" is not as
clear/correct as "last window closed."

[Andrew T Wilson (Slow), 2011/05/11 23:00:48]

My concern with the alternate wording is it sounds like checking the box would
keep chrome running in the background regardless of the presence of background
apps.

In any case, the strings I've added are basically verbatim from Jeff Chang's
email, and they'll go through UI review once I've landed this.

+      </message>
+      <message name="IDS_CONFIRM_EXIT_BACKGROUND_MODE_BODY" desc="Confirmation displayed when disabling background mode via the status tray context menu when there are no windows open">
+        Are you sure you want to quit Chromium? (This setting can be toggled in <ph name="OPTIONS_MENU_LABEL">$1<ex>Options</ex></ph> - Under the Hood)
+      </message>
       <message name="IDS_CANT_WRITE_USER_DIRECTORY_SUMMARY" desc="Summary of problem displayed in dialog when we can't create a directory for this user.">
         Chromium cannot read and write to its data directory:\n\n<ph name="USER_DATA_DIRECTORY">$1<ex>C:\Documents and Settings\devint\Local Settings\Application Data\Google\Chrome</ex></ph>
       </message>
       <message name="IDS_EULA_CHECKBOX_ENABLE_LOGGING" desc="The label of the checkbox to enable/disable crash and user metrics logging">
         Optional: Help make Chromium better by automatically sending usage statistics and crash reports to Google.
       </message>
       <message name="IDS_PROFILE_TOO_NEW_ERROR" desc="Error displayed on startup when the profile is from a newer version of the product and can not be read">
         Your profile can not be used because it is from a newer version of Chromium.\n\nSome features may be unavailable. Please specify a different profile directory or use a newer version of Chromium.
       </message>
       <message name="IDS_PREFERENCES_UNREADABLE_ERROR" desc="Error displayed on startup when user preferences file can not be read">
@@ skipping 186 matching lines @@
         <message name="IDS_UTILITY_APP_NAME" desc="The utility application's name.  Should contain the Chrome application name (IDS_PRODUCT_NAME). Example: Google Chrome Utility.">
           Chromium Utility
         </message>
         <message name="IDS_SHORT_UTILITY_APP_NAME" desc="The utility application's short name, used for the Mac's application menu, activity monitor, etc. Example: Chrome Utility, not Google Chrome Utility.">
           Chromium Utility
         </message>
       </if>
     </messages>
   </release>
 </grit>