Add "Keep chrome running in background" preference.

chrome/browser/ui/webui/options/advanced_options_handler.h

Index: chrome/browser/ui/webui/options/advanced_options_handler.h
diff --git a/chrome/browser/ui/webui/options/advanced_options_handler.h b/chrome/browser/ui/webui/options/advanced_options_handler.h
index 5b9c2f3878ea751afc9456c16fa44c1fe7be464b..6b59944421527e81d5bd20ebc1a05ebabba16f40 100644
--- a/chrome/browser/ui/webui/options/advanced_options_handler.h
+++ b/chrome/browser/ui/webui/options/advanced_options_handler.h
@@ -116,6 +116,15 @@ class AdvancedOptionsHandler
 
 #endif
 
+#if !defined(OS_MACOSX) && !defined(OS_CHROMEOS)
+  // Sets up the checked state for the "Continue running background apps..."
+  // checkbox.
+  void SetupBackgroundModeSettings();
+
+  // Callback for the "Continue running background apps..." checkbox.
+  void HandleBackgroundModeCheckbox(const ListValue* args);
+#endif
+
   // Setup the checked state for the metrics reporting checkbox.
   void SetupMetricsReportingCheckbox();
 
@@ -154,6 +163,10 @@ class AdvancedOptionsHandler
   BooleanPrefMember ssl3_enabled_;
   BooleanPrefMember tls1_enabled_;
 
+#if !defined(OS_MACOSX) && !defined(OS_CHROMEOS)
+  BooleanPrefMember background_mode_enabled_;
+#endif
+
   FilePathPrefMember default_download_location_;
   BooleanPrefMember ask_for_save_location_;
   BooleanPrefMember allow_file_selection_dialogs_;