Add "Keep chrome running in background" preference.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index c09de6fe7d0a508281763ddaac7a29ae6a6cd54a..60fdb3852d18a828f56cc9f605e20e362638bee0 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -224,6 +224,10 @@ Other platform defines such as use_titlecase are declared in build/common.gypi.
         <ph name="APP_NAME">$1<ex>Extension</ex></ph> has crashed. Click this balloon to reload the extension.
       </message>
 
+      <message name="IDS_KEEP_CHROME_RUNNING_IN_BACKGROUND" desc="The checkbox in the status tray context menu that controls whether chrome keeps running in the background after the last window is closed">

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

Should probably be "Chromium" rather than "chrome"

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

Good point. I've broken this out into separate chrome/chromium strings.

+        Let <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> Run In The Background
+      </message>
+
       <message name="IDS_SHOWFULLHISTORY_LINK" desc="The label of the Show Full History link at the bottom of the back/forward menu.">
         Show Full History
       </message>
@@ -8312,6 +8316,9 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_OPTIONS_ADVANCED_SECTION_TITLE_CLOUD_PRINT">
         <ph name="CLOUD_PRINT_NAME">Google Cloud Print</ph>
       </message>
+      <message name="IDS_OPTIONS_ADVANCED_SECTION_TITLE_BACKGROUND">
+        Background Apps
+      </message>
 
       <!-- Multiple download warning-->
       <message name="IDS_MULTI_DOWNLOAD_WARNING" desc="Warning invoked if multiple downloads are attempted without user interaction.">